UMTS / 3G Novatel Merlin U360 in Mepis (Vodafone)

Hi there, im impressed, as i plug in the Novatel Wireless Merlin U630, Mepis immediately uses c_serial to assign the adress /dev/ttYS0 to it, the leds begin to blink blue, which tells me the card has found its carrier and authenticated with it (pin mode turn off, no pin is ask),using atz+csq gives me a network quality about 10, and dialing up is no problem either (using minicom or kppp oder whatever), immediately authenticated via chap, pppd pops open and tells me theres a connection, just wonderful!!

Now the big issue, i do can ping google and resolve hostnames and log into jabber and see the online contact list, but thats it, the speed hardly rises above 500 or 800 B/s and I can't manage to get any few Ks send in sum, it just seems theres a huuuge bottleneck in this connection. Im using RC2, the Card runs fine in windows, if I could get this to work itll be my very latest computer to abandon M$ from it..

Windows network stats tells me any compression is off, is there a compression default set in linux, where is it set, any ideas ? Ill be so happy for help and to get this work,

Many thanks,
Gletscher