en til mange til mange reference?

I have a form and 2 subforms linked together. The first form has Contract number. The next has all Invoices for this contract and the third one has all payable elements for Invoice.  I can open the forms in this way and it works. I end up looking at the first invoice within this contract.
DoCmd.OpenForm "Contract", , , "([IDContract] =" & Me.[IDContract] & ")"

But my problem is, that I must go directly to a specific Invoice and i Have the unique record number, but I can't set it up to work? How can this be done.
I have tried this in many ways but without success. 
DoCmd.GoToRecord acDataForm, "Contract", acGoTo, [IDInv2] = 29004

Vh. OMN