Expose userid field in the Check in/out web service

Hello

I need to integrate the Check in/out web services into a InfoPath Library Form. I have the webservices added and working properly. My progress thus far:
              -CheckinFile, CheckOutFile, UndoCheckOut data connections are added
              -Necessary rules are built
              -Web services appear to work correctly EXCEPT

1. I receive an error if the form is opened in Browser, but not when opened in InfoPath Filler. This is a problem because most of our users do not have InfoPath installed. So we have a need to open in Browser or dialog.

2. Once the file is checked back in, the field "Checked Out To" defaults to an application ID.

So two issues:
How to open the form in Browser
How to set the Checked Out To field to the current user.

From what I have been told, I need to expose the userid element in InfoPath designer.