Default Question Dev's Read Please

Sorry if i put this in the wrong place since its something im developing a rom it should be fine. I'm putting together a custom rom for MetroPCS users and there's just one thing that i haven't been able to figure out, how to change the decompiled rom's APN settings? I remember once when I had my Eris i saw someones vendor tree and I saw the APN settings there but idk how it works on the EVO. I know there's a apn-conf.xml in the /system/etc folder but that one isnt it. I'm using dsxida's rom builder. Any help will be appreciated.