OAM 10g an OID 11g: CCB Userid maximum 8 characters

I need to integrate oracle CC&B application with OAM but CC&B uses userid with maximum 8 characters.

Oracle Internet Directory is integrated with Active Directory that does not have this limit of 8 characters.

So what i have thought is to create a new attribute for every user that is filled with the "version" of user-id in 8 characters, example:

userid: john.smith@domain.com become jsmith .

Is it the correct manner to approach this kind of problem ?

Is there some functionality in Active Directiory or Oracle Internet Directory that makes this out of the box ?

thanks