If you search the CW/Digital subforum I think that you will be able to find the information that you are looking for.
I have not any problems in configuring MultiPSK or Hamscope to decode CW. I do not own MixW but understand that it is an excellent program as well In order to have any digital mode program work properly with CQ 100 it is important to set the Recording Control Panel to Stereo Mix. Again this is outlined in detail in the CW/Digital subforum.
Once you have CW working with any of these programs then it is easy to experiment with some of the other modes such as PSK or RTTY.