Canadian citizen- cross chargeability

[canadian33]

Hi all…..
I am a Canadian citizen born in India. I 140 is approved under Eb3 with priority date of 24 April 2004. Originally, I opted for consular processing at Montreal. During 2007 visa bulletin fiasco, my wife, one daughter and myself moved to the US and applied for I485 and the applications are pending since then. One of my daugter’s remained in Canada to attend university hoping to do consular processing from Canada.
My wife is born in Dubai and I may be eligible for cross chargeability. When I applied for 485 my lawyer made only a vague reference about this in the covering letter. In February 2008, NVC send Fee bills to all of us and my lawyer remitted fee for my daughter who remained in Canada and intimated NVC that all three of us have opted for AOS. We haven’t heard anything from them since then. Like other people from India, I am frustrated about the long wait to get Green card.
The working condition with the present employer is not that great. I would like to use portability, if cross chargeabilty is a real possibility……..if not, I don’t want to jeopardize my greencard. My dilemma is how to get cross chargeability? During the last couple of months, I repeatedly asked my lawyer to write to USCIS about my eligibility for cross chargeability. She is against that idea. According to her, USCIS has no mechanism to respond to that type of letter. They will just ignore it. She is thinking that since NVC sent fee bill they recognized the cross chargeability (I am not sure about that). She is counting on the fact that since we informed NVC about my AOS, NVC will contact USCIS and USCIS will come to know about my eligibility for cross chargeability and accordingly apply the cross chargeability. Could anybody else share their experience in writing to USCIS for cross chargeability? Somewhere in this form I read they got a standard reply. Could somebody please advice what is the best course of action for getting cross-chargeability?. Thanks a lot in advance!