RTF <-> RTFD anyone? How to display RTF with embedded images (Windows) in NSTextView on a Mac and vice versa?

I have some RTF data shared between Windows and Mac. I use RichEdit control to edit this data for Windows and so if user inserts some images, I get the RTF with embedded images.

Now I need to display (and edit) this data on a开发者_C百科 Mac, but NSTextView supports only RTFD (rtf with attachments) and just skips embedded images.

What is the proper way to convert RTF with images (Windows) to RTFD (Mac) and vice versa? Has anybody done this before?