I am using 1920x1080 files from EX1 and when I am changing my project properties to SD widescreen my slow motion is strobe like; in HD everything is OK. Why and what to do to produce SD widescreen file for customers who don't have BluRay's yet.
thanks in advance

I would leave the project properties as HD and simply do the final render to SD MPEG2 (leaving the project properties as HD). The "strobe like" effect you are seeing sounds like it could be interlacing issues.

if I leave it as HD but final render to SD it is still strobe like;
when I work in HD properties and apply slow motion to the clip, render it to HD and then import to SD widescreen properties project then there is no strobe but it is pain going back and forth

I think I'd live with the pain to get the look I wanted.

Have you tried nesting the VEG file of your project into a new SD project and then rendering that way? Might be easier than going through the intermediate render.

For the best slow motion appearance shoot in 60i. For the worst, shoot in 24P.