TGEA Double Sided Poly Error

We are working on a project that has a ship with sails. The sails are a double-sided polygon. When viewed in Showtools, it works great. But when taken into TGEA, the sails are black and anything attached to that texture are as well. What I dont understand is WHY? Is this a bug that can be fixed? A feature that is 'supposed' to be there or what?

Any help would be greatly appreciated.