Hi pp - re copy/paste - if you are in contact with their tech support you might forward them this link from a post in another forum:
http://www.spaceclaiming.com/xn/detail/2118765:Comment:10601

That gives some information on how to make a Copy/Paste function that will work between MoI and also Rhino. Basically it is just a 3DM file that is stored in the clipboard, so it is probably pretty easy to add support for this if you already have support for 3DM files.

EDIT: now that I think about it, they probably like to do Copy/Paste in both directions, and the backwards direction (from Paint into MoI) would not work in this case since they convert to polygons like you were mentioning. So this would be for a kind of one-way paste from MoI into their app and not backwards.

- Michael