Retrieving InnerXML in PHP DOM

Hi,
I'm trying to return the inner XML from a DOM element, but I can't find
any methods that allow this.
For example, if I have a string:
<TEXT>Here is a string with <B>bold</B> text in it</TEXT>
then I want to return the enclosed string _including_ the <B> tags:
"Here is a string with <B>bold</B> text in it"

Using get_content strips out the tags.
"Here is a string with bold text in it"

Does anyone have any suggestions?

Cheers,
Jason