asterisk users - Jun 2006 - DTMF Detection Problems on VGSM channel

Hello Asterisk Community,
I'm using Voismart's GSM PCI cards to connect Asterisk to GSM cellular 
network.
The problem I face is DTMF detection; that is, whenever I call to one of 
the channels (SIMs) on GSM card through my Mobile phone, and dial DTMF 
digits while in the call, the Asterisk receives almost all the digits in 
multiple samples.
e.g. I dial 123456789 and Asterisk receives kind of 111223333455678999.
I tried to change the DTMF settings on my Mobile phone (There is one on 
my phone); Changed "DTMF type" to Long, short... did not help.
I guess those GSM cards have problems in DTMF detecting algorithm (I 
think DTMF detection burden lies on GSM cards)...
Has anyone faced this issue, or I'm the one to struggle?

Thanks for your comments.
Regards,
Hohenzolern