Can you use XPath variables in RCDC? Or only environment vairables? I do not want to use environment variables. Example: < my:Property my:Name="Peace" my:Value="Joe_Smith" /> < my:Property my:Name="Value" my:Value="/Group[(AccountName='%Peace%')]" />

You can, but it depends on what you are trying to achieve! This is a good reference for writing XML for the RCDC: http://technet.microsoft.com/en-us/library/ee534918%28WS.10%29.aspx

I have read the xml guide, but could not find what I am looking for so I posted the question here. I am trying to create a dynamic filter based on the variable I provide. I can't seem to find any code snippets or that it is even supported.

Looks like the best way to do this is through a custom workflow. Only attributes you can use are the common ones in the RCDC. You can see how I did this in this thread: http://social.technet.microsoft.com/Forums/en-US/ilm2/thread/d044c28f-4d12-47d8-97bb-e36e329e4e86