OpenType Fonts (OTF) is a superset of True-Type. OTF may contain either PostScript or True-Type font data. In the latter case it is possible to use OTF for creating PDF documents. It should also be possible to embedd True-Type OTFs in PDF documents using VPE. But since OTF contain some additional tables with font information, this may not work for every font.
I'm having problems with a OpenType font at a clients site - but I suspect that the used OpenType fond is a PS font, and can therefore not embedded by VPE.
Is anything like PS font embedding planned for a later release?