Dennis,
You already know I am not a PRA nor a P6 user as they do not provide enough resource modeling capabilities for my needs. Anyway the issue of risk modeling is universal and I am interested on what Primavera brings.
Of course using PRA while using P6 to manage resource leveled schedule makes no sense as the resource leveling schedules will differ, in many cases by a substantial amount.
It might be you cannot export the file from P6 to PRA but that you must use PRS to import.
http://www.slideshare.net/jisothomas/concepts-and-best-practices-for-the-risk-register-in-primavera-risk-analysis
The following might be of interest to PRA users as it provides some suggestions for risk mitigation and a few hints.
http://www.slideshare.net/jisothomas/concepts-and-best-practices-for-the-risk-register-in-primavera-risk-analysis
Good luck.
Rafael