You're right, seems I used that link, I'm running ISXfuse 2.7.2

Can't agree with that. It works for me under 10.10, I have both MacFuse and OSXFUSE running. Don't remember how exactly I did this magic, was lazy to document that at a time. But I have completely NO issues with writing to IMG images now at 10.10.

Great news, PCE developer has sent windows binaries which have serial port support enabled! I tested it works

My disk images are in .dsk format, this emulator uses .img format. The img disks won't open in hfvexplorer. IMG to DSK is easy if you're on OSX 10.10 . Install Macfuse and rename both to DMG :) Now you can read and write it. Once complete then rename DMG back to IMG. That method worked great for me...