Copy user entries from a server to another?

Hello. Is it possible to copy user entries from a server to another? I have a user that connects to a "foreign" Radius server (AAAF). The AAAF detects his realm and forwards the request to the realm's appropriate Radius server (AAAH). The AAAH authenticates the user and returns the result. What I'd like to do: copy the user entry to the AAAF (username, password, check items, reply items) so that the AAAF can later authenticate the user without having to forward the request. Is this possible? Furthermore, how could I keep the user's data, seeing how unlang doesn't support creating new variables? Any advice is welcome.