RB433UAH with two Huawei 3G USB

Hi,
i’m trying to get RB433UAH with ROS 4.3 working with two USB 3G modem (Huawei E220).
Both modem work regularly alone, but I I try to use both of them i’m able to see on a port (usb2) so I cannot start second ppp-client connection.
Any idea abot how to get them working?
I need two modem to sum prepaid traffic of two sims (20G+20G or 300h+300h).
I’m trying to write a script to bring down connection with exhausted traffic ad bring second one up (any suggestion is appreciated).

Thanks
Luca

me too. anybody help?
any further infomation?
does rb433uah really support two 3G modems at same time?