The proper way would be to send off a tape master for a HD foreign conversion.
But if you are only going to use what you have, try exporting to 1080/25p when making the mpeg file.
I recently received a 108025p PAL clip. Converted it to 24p and it did the job. But you run the risk of speed change/pitch shift and lipsync issues, depending on what you’re working with.
Chris Tompkins
Video Atlanta LLC