Wow! How much time do you have? Just kidding...
To start, I should point out the difference between eBM and Web Services.
eBM provides an "Out of the Box" solution to create web pages linked directly to your MAS 90 / MAS 200 AR, SO and IM module data sets. Based upon various options you can select you can define relationships in your products a multitude of ways and these relationships are independent from how they are set up internally. The products pages are dynamically loaded based upon these relationships defined. The objective was to provide a relatively "quick" means of developing a web site within MAS 90 / MAS 200.
Web Services provides the means to communicate with your MAS 90 / MAS 200 installation. Primarily, it provides a means to create sales orders from a web page that "you create". In this scenario, there are no templates per se. Nor is there a direct link to your data sets to dynamically load web pages. This opens up your web pages to be anything you wish, using any web authoring tools you wish, etc.
As you can see they are 2 totally different things, satisfying 2 totally different objectives. On your MAS 90 CD there is a Documents folder. In that folder there is a document that provides a much better explanation of Web Services. There is also a eBusiness Web Services Examples sub-folder that may help.
Now on to eBM tokens and customizing eBM templates ...
In Help there is quite a bit of information on this. Under e-Business Manager select the Working with ..., then check out the help included for "Templates" and then "Web Pages". This will give you a pretty good overview.
When discussing tokens specifically, let me first just say that these are simply place holders in the HTML template. You can easily identify them as they will always start and end with ~~. There are 2 basic types of tokens, data tokens and processing tokens.
The simplest is a data token. When the HTML template is rendered, the web engine will replace these tokens with the actual data. Data tokens are always ~~TableName.ColumnName~~ or ~~TableName.ColumnName$~~ . Note the $ is added when the column is not a number.
Processing tokens identify specific ProvideX code to run. When the HTML template is rendered, this code is executed when encountered by the Web Engine as it parses through the template. It is used to dynamically insert HTML markup. The main example is when adding the product rows on the products and services pages or the items added to a users shopping cart. The format for these tokens are ~~ ProgramName;Label ~~. When this token is going to be part of a link that will load a new page, you will see the ISAPI redirect (.pvx?) included ~~ ProgramName.PVX?;Label ~~. This is the special code used by the plug-in to know when to process a eBM Template.
Finally, there are some special handling identifiers that can be included on a token. The 3 you will see most often are ?a, ?x and ?t
?a tells the web engine to render the code exactly and to not escape any HTML markup. This is needed when the token value being inserted will include HTML markup. If you do not include this identifier the < html markup is translated to >
?x indicates the token is a formula. The web engine will solve the formula and substitute its results when rendering the page.
?t indicates a dynamically loaded table. This is a "special" processing token. It identifies the location of the logic to run necessary to dynamically fill a table. What makes it special is the row just beneath it is used to load the table row. So when you see <tr><td>~~ ProgramName;Label?t~~</td></tr>, the table row just after it <tr><td>~~TableName.FirstColumnValue$</td><td>~~TableName.SecondColumnValue$</td></tr> is what will actually be used to fill the table.
The Customize Your Web Site.doc attachment is an overview I did when the eBM frame work implementation was first done. It goes into a bit more detail than my description above.
The Customize Sample.doc was created to provide a "How To" guide to help explain adding UDF's to the eBM HTML templates for both header and detail table scenarios. It was done at the same time as the Customize Your Web Site.doc and includes the HTML markup edits with explanations.
There is a zip file (that I was unable to attach) that includes the HTML templates used to do the screen shots in the doc and a Customizer import to set up the UDF's used. Since this was originally done for Customer Support, you (or your reseller) should be able to get a copy from them if you would like to have a copy of it for a starting point to play around and try the sample out for yourself.
Hope this helps.
GatorGal
( I hate reading documentation ) ...and yes, I do have a significant amount of time. 
