Question about daughter being approved for visa

[pyndi]

I have asked this question in another forum but asking again because I really don't think I asked in the correct section. So here it goes.
Me and my daughter are US citizens. My husband is a UK cit. We are now living in the US but he wants to go home asap. I see no problem with me getting a spousal visa. However I am worried about my daughter. She is not my husbands biological child. Her father has had no contact with us in over 2 years. I have no contact info for him or his family. Prior to the 2 years he only visited occasionaly. Now his name is NOT on her birth certificate and it is NOT on her passport. We also were never married. I have asked someone at Woodbridge and all she said was what do you have to prove you have custody I'm like I guess just the birth certificate and the fact I have claimed her as my dependent on my taxes since she was born. The lady at Woodbridge said that would be fine just send a letter along but I have a gut feeling that's not right. Do any of you have personal expericnce with this? I am thinking about going through the courts and getting sole custody but it cost $500 and with all the other expenses I really don't have that right now. If I knew for sure it didn't matter I would save my money. Let me also add that about 5 years ago I was on public assistance and the courts went after him for child suppport, which he is yet to pay. There was never any paternity test just my word that he is the father and him not denying it.

[vinny]

See also sole responsibility.