Ask the coach if it's mandatory that she wears the team gear. Complaints about discomfort or poor fit might help your case. If it's mandatory, you might be able to swap the straps from the All-Star legs to the LS legs (just remember to swap them back at the end of the season).
I'd make the team buy some straps that were comfortable. Otherwise wear your own gear. As a coach, I could care less what color the catcher's gear was, or who provided it. I guess I'm just not a very good micro-manager, nor a control freak.