XmlDocument does not contain a definition for…

Help!

I’m fairly new to BizTalk and am attempting to put together my first fully fledged orchestration, but have run into a problem I can’t resolve.

I have one orchestration calling another, using one input parameter message and one output parameter message. The called orchestration uses some decide shapes to determine what should go in the output parameter message, then creates it. All fairly simple stuff.

When trying to compile my sample I get three strange errors:

[code:1:711d2d28d2]’System.Xml.XmlDocument’ does not contain a definition for ‘Source’
‘System.Xml.XmlDocument’ does not contain a definition for ‘Source’
‘System.Xml.XmlDocument’ does not contain a definition for ‘EndDate'[/code:1:711d2d28d2]

These are the distinguished properties on my input argument that I’m testing in the expressions.

Looking at the generated .cs code I see something like this:

[code:1:711d2d28d2]__condition__ = __ctx1__.__Message_CollateralLine.part.TypedValue.Source.StartsWith(\"REPO\");[/code:1:711d2d28d2]

So it looks like the ‘TypedValue’ of my message argument is XmlDocument, when it should be the type of the schema. The arguments are set up as being the correct type.

I’ve been banging my head against this for ages to no avail, could anyone give me any pointers on where to look, what to check, or how to debug this problem?

Any help will be much appreciated!