I have the same problem that I can't use my ZTE 628 modem with my Trendtac Epc 700. I have found a Linux driver at this site:
http://lxr.free-electrons.com/source/drivers/usb/serial/option.c But I don't know how to get it working with our laptop. I dont even know if its possible. Perhaps someone can help?
I have also found another driver at this site (look under fundecke)
http://www.hecuba.at/ at the Eee Pc forum I read that this driver works, but does it work on a Trendtac or CnM Minibook?
Trendtac EPC 700 and Cnm Minibook have a special Linux distro and if the driver you have found are for Ubuntu or other distro they surely won't work.
I hope that someone on this forum could help!!!