And just to give you a vague idea of how it might work based on my limited understanding of the program...
You would need to set up the mic input option in Skype (if that is available... it should be but I've never used it) to accept the output from Voicemeeter (instead of from Windows or the system hardware).
Then you would set up Voicemeeter to accept input from Sonar's output (or maybe from your audio interface) on one of Voicemeeter's input channels. Then if you want to talk over top of it as well you would use a second input in Voicemeeter to accept the signal from whatever microphone you have hooked up (from whatever program you have the mic running through but probably just from Windows might be fine).
That is a VERY basic description of what I THINK needs to happen. There are a lot of things to be setup and and be considered so you'll have to really study the program and how to route things into Skype's audio input (as well as the inputs/outputs and driver settings of all programs involved).
Seriously this should work but it will take someone smarter and more experienced than me to walk you through it all.
Good luck.
PS: And are you going to want Sonar to to show up on the other Skype user's screen? That will likely require some kind of extra screen recording software. If it is just audio then that's easier.
PPS: However I just noticed you upated your info to say you have Win10. I do not own Win10 but I've heard that there is a built in screen recorder in Win10 that you may be able to use for live screen recording/video chat. I cannot say for sure though.
post edited by Beepster - 2015/09/05 13:08:59