TP2 Hybrid: How to modify settings for GSM data connection?

[a in yul]

Having just flashed MightROM on a hybrid TP2; I would like to know how to modify the settings for a GSM data only sim;

Using CDMA network data and voice works;
Using voice on a GSM sim card works;
Using data on a GSM DATA ONLY sim card DOES NOT work;

Where would i modify the settings? (Usual settings for FIDO are internet.fido.ca, name & password are fido, fido respectively).

Any suggestions would be much appreciated!

Cheers;

EDIT: i would like to use the GSM (quadband) network of this phone; (not CDMA voice and GSM data at the same time).