Sorry I was researching how to dye Nomex. The only thing I could find was a process called acid dye but the consensus seems to be that even that process is iffy at best. I have a friend that works in with industrial textiles. I emailed her to see if she has any ideas. The best I could find was this place that has dyes for synthetic materials( not sure if they would work):
Paints and Dye To Use On Synthetic Fabrics
Joanne fabric also carries a small selection of acid dyes.
Sorry that is the best I can do. If I hear anything from my friend I'll let you know.