InfoPath Dev

I have an InfoPath 2007 Filler Form Template that is used to submit forms to a SharePoint (WSS 3.0) forms library.  I have an ItemAdded event receiver applied to the library that reads promoted properties of the submitted form.  When a form is filled out and submitted using InfoPath 2007 (and Windows XP), then everything works fine. The event receiver is is able to read the promoted properties (aka fields/columns).  However, when a form is filled out and submitted using InfoPath 2010 (and Windows 7), then the promoted properties are not available to the event receiver.  My guess about what happens is that 1) the form is added to the library, 2) the ItemAdded event receiver kicks off and fails, and then 3) the form is updated with the promoted properties.  I also notice that it takes a lot longer for the form to be submitted using InfoPath 2010/Windows 7 than it does with InfoPath 2007/Windows XP. 

Does anyone have any insight about what is actually happening here or what the best way to resolve this problem would be?  I need to support both clients: InfoPath 2007/Windows XP and InfoPath 2010/Windows 7.

Note that I'm using a standard submit to SharePoint library data connection.

Thanks in advance.

 What are the bitness of operating systems ( 32-bit aka x86 or 64-bit aka x64) running  WSS 3.0, Windows XP,  Windows 7?

And if you are having 64x Windows 7, have you installed 32-bit or 64-bit MS Office/Infopath 2010 (32-bit is recommended)?

WSS 3.0 Server: Windows Server 2008 SP2 64-bit

Windows XP 64-bit with Office/InfoPath 2007 32-bit

Windows XP 32-bit with Office/InfoPath 2007 32-bit

Windows 7 64-bit with Office/InfoPath 2010 32-bit

Thanks.

 I was able to work around this problem by creating a Web Service to submit my forms rather than the OOTB Submit to SharePoint functionality.  The Web Service takes the entire xml of the form as a string input parameter. It also takes the name the form should have as an input parameter.  The Web Service gets the form library URL from the template location specified in the processing instructions in the xml. Doing it this way has the extra advantage over the OOTB functionality that it allows me to return user-friendly error messages to users, if there are any.  I wish I had gone this direction from the beginning.