WSTP Callbacks into CDF

Essentially, what I am trying to find out is the limitation of the WSTP/LINK protocols in Enterprise-licensed CDF. Specifically, are any callbacks to the kernel from those protocols allowed in CDF , Enterprise CDF, or Player Pro? Are any methods disabled?

This problem is difficult since very few people discuss the issue, and Wolfram documentation makes little mention of disabling specific functionality for CDF/Player Pro (e.g. http://www.wolfram.com/player-pro/how-player-pro-compares.html is not very specific). More importantly, if callbacks were allowed without any restrictions on what Evaluate could do, what would stop a person from evaluating arbitrary expressions using a combination of a LINK and IPC (i.e. interprocess communication)?

I have been told by Wolfram representatives that version 10 Enterprise CDF should have less LINK restrictions that the previous version (e.g. .NET/LINK is allowed now), but that still doesn't help me understand where Wolfram draws the line.

I appreciate any answers or suggestions. If I hear back from Wolfram on the issue, I will update this post.

While I do not work for Wolfram, so my answer is not authorative, I think that point e. under Prohibited Uses here indicates that WSTP callbacks are prohibited. This is also confirmed in this thread. You can call from within CDF an external dll, if and only if you have activated, i.e. paid, Wolfram CDF Player (version 10.0.2) to Wolfram CDF Player | Pro. According to this comparison, and my own experiments, it is unfortunately not possible to call your own "turbo"-dll (e.g. some speed-up of a special function created by CreateLibrary) from within an Mathematica-Enterprise generated (signed) CDF. So, while Enterprise CDF is just great in principle, it is still quite crippled compared to Player Pro (or the full Mathematica, of course).