I do have a friend who had a CASA CPL and went on to be a flight instructor with STAA. He's now flying with SilkAir. STAA is OK with Singaporean instructing in Australia. Afterall, it's a Singaporean company.
I've also heard of others who had CASA / NZ CPLs ending up with some flying jobs in Africa, clocking up hours and now flying with airlines in Indonesia.