I had a Huawei E173 dongle locked to Dialog and was able to unlock it successfully.
If that interests you, keep on reading...
Download the following stuff:
3. Unbranded dashboard (optional)
1. Run the code generator and enter your IMEI. Note the unlock code.
2. Run the new firmware installer and input the unlock code when prompted.
3. Optionally install unbranded dashboard software. (Dialog dashboard works with other SIMs!)