I finally fixed the storage provider issue! After reading a new KB article on how to review certificates inside VECS (VMware KB: Manually reviewing certificates in VMware Endpoint Certificate Store for vSphere 6.0) and reading more about VECS from vSphere 6.0 Documentation Center , I found that my SMS certificate was expired. I tried to use C:\Program Files\VMware\vCenter Server\vmcad\certificate-manager.bat, option 6 "Replace Solution User Certificates with VMCA Certificates" but it did not correct the problem. Deleting the SMS store from VECS and restarting all the services fixed it for me (take a backup before you do this!). For anyone with the same issue the command was: C:\Program Files\VMware\vCenter Server\vmafdd>vecs-cli store delete --name SMS
You can check if your SMS certificate expired before deleting it by running C:\Program Files\VMware\vCenter Server\vmafdd>vecs-cli entry list --store SMS --text
In regards to converting from VCS to VCSA, the VCSA doesn't support VUM yet which would result in needing another Windows machine to run VUM. Until VUM support comes with VCSA I probably would not switch platforms.
Sounds like KB 2079087 and 2078070 need an update for vSphere 6.0. Anyway, I wish that was my problem, but I checked and my SMS certificate is good for quite a while yet.
"A quick warning.. That fling is great.. when it works. There is still a bug where it doesn't work if your vCenter is on Windows Server 2012 R2, so don't waste your time if you're in that situation. I'm not sure what's taking so long to fix that issue. This is probably why the fling isn't officially supported yet."
My jaw dropped when i read that, what a shame Guess I should be thankful the VCS was 2008R2...