[Q] WiFi or 3G = some apps work somw other not !

[pacut]

I hope this is not OT

On when WiFi is on I have:
- exchange NOT syncing
- standard browser working properly
- Firefox working properly
- Gmail working properly

On when WiFi is off (3G is then on) I have:
- exchange syncing
- standard browser working properly
- Firefox NOT working properly
- Gmail NOT working properly

My SIM card has wap APN type and unfortunately that's the most I can have from my Company (who ownes the SIM itself).

I can't understand why I have so many limitation under 3G network, particularly for Firefox. Doesn't firefox use port 80 ?
Do you have any idea why all of that happen ?

Thanks
paolo