rewriting non-DN attribute values with rwm?

I'd like to rewrite the following entry:

dn: uid=user@olddomain.com,dc=olddomain,dc=com uid: user@olddomain.com mail: user@olddomain.com

to appear and behave like this:

dn: uid=user@newdomain.com,dc=newdomain,dc=com uid: user@newdomain.com mail: user@newdomain.com

I can get the DN rewritten with slapd-relay and rwm-suffixmassage, and can use rwm-rewriterule with the searchFilter and searchEntryDN contexts to return the entry when querying for mail=user@newdomain.com. But I can't figure out how to rewrite the *values* of the uid and mail attributes in the returned entry to user@newdomain.com. What is the best way to achieve this?

Thanks,

-Kartik