rails xml_builder: how to insert existing xml blob into the partial?

Question

Simplified version of my problem:

I have some variable, that contains some xml. x = "foo

I'd like to generate XML that looks like this: x <-- contents of x

So I have an xml builder partial that looks like xml.map do xml.other_stuff do end end

how do I insert x in there?

If the question isn't clear just yell at me and I'll retype. 3am does not a pristine query create!