I do not believe that DESIGNER X4 supports the latest Freehand formats (from memory, only up to version 8 or 9). This forum is a great place for this kind of feedback. A work-around is to use Freehand to save your files in a format that is supported by DESIGNER. I haven't used FH in quite a while, so I am not sure if there is a way to automate this through a batch process.
I would be interested in learning more about how you use FH and what type of Technical publications you create. Feel free to contact me through private message when you have a moment.
Regarding the date DESIGNER X4 will be available, sorry, but I cannot answer that (yet).
Gérard