Using MS SQL2005, I have created a table function. Although you can see it in CR2008, when I try to access it directly I get an error message
Database Connector Error: 'ADO Error Code: )x
Source: Microsoft SQL Native Client
Description Line 1: Invalid procedure number (0), Musst be between 1 and 32767.
SQL State 42000
Native Error: [Database Vendor Code: 1005]'
I think it may be to do with the fact that when you select from your table function in MSSM you need to put the parameters in parenthesis and even if there are no params, you still need to add the brackets to the function call.
The solution to this is to create a view which calls the table function. This view is then available to CR2008.
HOWEVER...
If you then change the columns that are returned by the table function, the CR dataset is not automatically updated. In order to update the dataset, you need to edit the view in MSSM and re-save it, then go into CR2008 and right click on the table and Set Datasource Location. Your new data should now be available for the report.
This is fine for one table, where you know the data has changed. If you are not sure, or have serveral data maps that have been modified, then it is probably best to use the menu option Database->Verify Database.