FreeRadius using two SQL servers

Hi, my version of FreeRadius is 1.0.5 and what I'm trying to do is that when a radius client ask my freeradius, if the Realm is "xxxx" I want to autorize him with the first SQL server and if the Realm is "yyyy" with the second one. I already have two diferent sql configuration files, sql1.conf and sql2.conf, with instance name SQL1 and SQL2. I had been trying to do exactly what the Autz-Type Doc says, but I had no luck with it. I don't know what to do... Thanks NanO