Unlocked verizon BB9930 able to use Singtel Network but no BIS logo while dataroaming

[s15nic]

Having an unlocked 9930 by Verizon. Working perfectly fine in Singapore's Singtel Network however when roaming, BIS logo does not appear when roaming overseas (only showing name of roaming network with 3G, without BB logo). Unable to use any data services at all for ALL applications in the phone.

Have checked with Blackberry Customer Support (RIM), recommended to use a local (singapore) BB 9900 for troubleshooting, no problems with roaming at all.

Actions taken:

1) Host routing table registered but no 'device registered with wireless network msg' sent back while in roaming network

2) Service books for network resent however unable to work while roaming ( BIS unable to register in foreign network)

Seeking advice what settings or steps have I omitted? Thks