I think it's going to be tricky. You will be using the logitech headset as your soundcard in this instance, and this will be set up as the audio mic and "speakers" in Skype. In reaper, you would need to select the logitech headset as your card, and select the microphone as the input to the track you are recording. Now, on an audio interface, you could take the outputs and feed them into inputs and record them, too.. but you can't do that in this instance. Also, you have the problem that Reaper will want control over the headset and so will Skype. This might be simple if you had an audio interface with a microphone and separate headphones, but I can't see a way of doing it with Reaper using the logitech headset. HOWEVER, take a look at "Pamela" (a Skype addon, or "extra" as they call it), which is designed to record Skype calls. It will even save the calls as MP3s if you like (to save space). You could always load the recordings into Reaper later to clean them up or edit them if you wanted to.