Project settings for 50p @ AVID 5.5.3.?

Hi,

my material is shot with 720p@50p (with HVX200), thus now exists as MXF files.

When I want to change the project settings for AVID Xpress Pro 5.5.3. (PC) to the named format, I can choose among

- 1080i/50
- 25p PAL
- 720p/59.94
- 1080i/50 HDV

Which format should I choose?

I tried all of them.

If I want to look at the files, then message "Clip frame rate (50) does not match project frame rate (25)" appears.

What should I do?

Or can't I work with 720/50p at 5.5.3.?

Thanks!