Type string with a XML

Hi people!

I have a special situation. In my IN schema (xml1) I have a string element, but really this element is a XML document putted in a string. I need some elements of this XML (xml2) and my idea was use a Assigment where I create a XMLDocument variable to extract the xml2 of the string and then I assign this var to a message with the schema of this XML. But the problem is that Biztalk doesn't recognize the xml1 with the element like a string because it think that the first node of xml2 is a subnode of xml1.

The solution that I think is create a new schema composed with both xml to prevent these problems but it seem me some unprofessional, I would prefer some way to solve it without the creation of a new schema.

Thanks!!!