B:
I know nothing of international name change. But, I would think that being in Germany has nothing to do with whether or not you can change you name on your Bangladeshi passport.
Also, if I infer what you are saying, it is impossible to change the gender on your passport from male to female (or female to male).
Returning to your home country shouldn't be a problem unless you are strip searched. Your selected gender will not be obvious unless they look between your legs.
Without more information about your issues we really can't give you any more advice than that.
Also, hon, you may have tried to create a regular post, but you created a poll instead. Next time select "New Topic" when you want to post a message. It looks like you selected Post a New Poll.