Lookup in a array of records

This is probably simple but how do I do a lookup of a field within an
array of records?

Given the following:

     d g_FunctionList...
     d                 ds                  Qualified
     d                                     Based(ptrFunctionList)
     d                                     Dim(32764)
     d    FunctionName...
     d                               50a
     d    ServiceProgramName...
     d                                     Like(StdNam)
     d    ServiceProgramLibrary...
     d                                     Like(StdNam)
     d    ServiceProcedure...
     d                               64a   Varying
     d    pptrProcedure...
     d                                     Like(StdPrcPtr)  

I want to do a lookup on the function name. This code does not work
because the sizes are different. 

Position = %Lookup(Function       :
                   g_FunctionList :
                   1              :
                   g_FunctionCount);


This does not work because it wants the index. 

Position = %Lookup(Function                    :
                   g_FunctionList.FunctionName :
                   1                           :
                   g_FunctionCount             );


Redefine with an overlay?

Thanks for the help.