I too suffer from shy bladder, so I feel your pain. I'm a male suffering from GID, wanting to be female. Oddly enough, I can urinate in the women's bathroom no problem. I've always urinated sitting down. I never understood why guys stand. In fact, I think I developed shy bladder because I was afraid of guys seeing my legs in a sitting position under the stall door, but hearing the tinkling noise of urine.
Lack of attachment to my genitals also played a large part. When you don't feel connected to them its kinda hard to get them to do the bodily functions required of them.