Hi Mark,
I am not aware of any plugin or app that would do this. Unfortunately, the .rep and .sit file types have been notoriously unstable throughout X-Plane history, sometimes even breaking between updates in the same major version (files saved in 10.30 don't work in 10.50 I believe).
This is something we hope to fix for X-Plane 11, so that your situations and repays will always work in version 11 at least.