I tried this a couple of years ago without success. I think LPS uses radians and Photoscan uses degrees for the rotational angles. I would look there first. I also recall that some of the angles are negative in one model vs. the other. It should work once you figure out the conversion.
I've got a couple of LPS tuts on youtube that might help but aren't Photoscan related:
https://www.youtube.com/watch?v=byF9AxlXhRMHardest part of figuring it out, are finding the lens distortion coefficients that work. The conversion model that Photoscan has for LPS was incorrect the last I tried.
In my opinion, if you're just trying to make accurate photogrammetric models, drop LPS and focus on the awesomeness of Photoscan. You'll save a ton of money and your models will be more accurate.
-Mark