Hi David,
I'm a bit rusty on sketchup, but I think you need to have PREMIUM access to be able to use the extra Psets on TRIMBLE CONNECT.
For your information, here is a video.
https://www.youtube.com/watch?v=3JwAq8fPbXs
Have you tried by creating an IFC in sketchup? Maybe this would solve your attributes problem?
BR
David
PS : quick test with IFC

