Yes you can, i have the Viasat Baltic card here.
to get the card work you need
1) original tuner
2) STB ID converted to Hex
3) OSCAM
As soon as you have the STB ID converted to boxid / hex format then you can add this to the oscam config file.
Viasat works only with the SD channels as long as i know, i have heard rummors that even HD works and have seen this, but i do not know how is made or who makes this possible for Scandinavian. Baltic countries i have not seen any HD from Viasat