Using Functions in OIM Sandbox customization?

Hi all, I have a need to do some string comparisons in my OIM 11gr2 environment.  I was attempting to use EL to determine if a description contains a certain string i.e.  something like

#{fn:contains(oimcontext.currentUser['Organization Name'],'ADMIN')}  but I'm running into an error: Expression uses functions, but no FunctionMapper was provided.  I tried adding the xmlns:fn="http://java.sun.com/jsp/jstl/functions" tag to my mds:attribute  at multiple levels to no avail.  No matter what I try, OIM doesn't recognize the function within the UI.  Is what I'm trying to do possible within the EL?  Is there a different way I could accomplish the same thing (short of a custom java bean as I'm trying to keep this simple)