Modifying authorization replies by a proxy

Hi, when the FreeRADIUS is configured as a proxy is there any way to modify the authorization replies (Access-Accept packets) before sending them to the NAS? I need to add there a few attributes (purchased connection speed etc.). Reply attributes in the 'users' file of the proxy seem to be ignored. For example, with the following record in the 'users' file proxying works well but the Framed-IP-Address attribute seems to be ignored: username Proxy-To-Realm := xxx Framed-IP-Address := "2.2.2.2" rlm_attr_rewrite does not seem to be useful in this case as I need to define the rules on a per-user basis. (FreeRADIUS 1.1.6) Martin