hello
so VMware Horizon View 5.2 supports MS Lync. There is a plugin that is installed which allows the audio and video to be terminated at the client end point. As such, you should not need to redirect the webcam or audio using RTAV to the desktop.
There is a blog post about it here: The ABCs of Deploying VMware Horizon View 5.2 with Microsoft Lync 2013 | VMware End-User Computing Blog - VMware Blogs
or checkout the docs here: http://www.vmware.com/files/pdf/techpaper/vmware-horizon-view-microsoft-lync-install-configure.pdf
With regard to Real-Time Audio-Video, then we DID test it running "in conjunction" with MS Lync. ie, you have lync installed, but also want to use Skype or Webex in the guest desktop. Then we did test that MS Lync will "play nicely" with the Virtual webcam. ie if a call is active using RTAV then MS Lync will not be able to access the webcam, and if a call is active in Lync then RTAV will not be able to access the webcam.
Hope this helps
cheers
peterB