Hey guys,

Had the same problem a while ago.

Instead of waiting or downloading a beta version I emailed sketchup and told them my situation.
They were able to send me a temporary pro license activation code for SU2014 so that I could use my Maxwell
Render plugin for another while.

Taking in to consideration that plugin for SU2015 is not fully complete I might ask them for this favour again.

It is definitely worth a try.

Good luck!