If you have a minus sign and an edit function do one - sign then do a second one over the top turned 90 degrees in edit mode. That should make a +.
send me a PM with your email. I have done one in 20 mm size or do you want it larger smaller. Sory not tried it out
If you have a regular sewing machine you can zig zag as satin stitch + sign the size you want to get around it with the same thread you are using. Hope this helps...Suzanne
Loosie what format are you working in and what style is the font?
I work in PES and the font is what came with the brother machine, don't know the name but its plain