If you have the Reallusion Board Shorts, or if you want to by them in the Marketplace for $5 link Classic Shorts Base - Character Creator/outfit - Reallusion Marketplace, I have made an opacity map to use for the female avatars
who would wear the board shorts. I have made a UV Map also with stripes at the bottom for male and female characters.
You can download the Maps below if you would like. You can download the tennis shoes from the youtube link. 

Here are some diffuse maps with stripes and without stripes. These are for the Reallusion Board Shorts ($5) from the Marketplace.