CS2k2 - Adventures in catalog managment

I was at a client today and I ran into a problem with the Commerce Server product picker and the expression builder. It seems that when you use a property definiton that contains an "_" for your product Id, it fails when you try to define an expression.  The error that is raised reads something like, "Unable to create expression. ProductID.Product_X5F_code could not be found".
 
It looks as though if the product id field and/or variant id field contains an "_" character (actually the code filters other allowed characters such as "-"), the code replaces the invalid character with a "_X{ascii numeric value of character}_" in order to create the XML node name for the data island. The code is in the APP_NAME_BIZDESK\Catalogs\Editor\common.asp page inside the sReplaceSpaces function. The "_" is a valid, allowed character for a product identifier field, "product_code" in our case, so I modified the code in the file to allow the "_" character and the expressions now work correctly. I have included the fix below.

In the Function sReplaceSpaces (ByRef sString)
...Some code here

Change the line:
((iChar >=  91) And (iChar <=  96))

To:
((iChar >=  91) And (iChar <=  94)) Or _ 
((iChar =  96)) Or _

...more code here
End Function