Workaround for the "The part 'part' of message" BizTalk annoyance

Working with BizTalk can be a frustrating experience for many developers. At least, that's the experience I've had with the tool. In any case, my latest annoyance was the dreaded "The part 'part' of message '{Message}' contained a null value at the end of the construct block."

Scouring the web for solutions turned up virtually nothing. And so it began, my journey for a workable solution to this enigma that is BizTalk (again). My first attempts were a simple exercise of attrition. It encompassed recompiling, re-referencing, de-referencing and every other ridiculously simple attempt to resolve the problem. None produced the desired outcome; the message persisted and my patience grew increasing limited.

Thus, my next series of attempted fixes resulted in reassigning the message variable. I'll spare you from the multitude of failures incurred before succumbing to the eventual fix.

The resolution consisted of the following:
1. Declare the outgoing message of type System.Xml.XmlDocument
2. Create an xPath string that will populate said outgoing message with the entire contents of the message to be leveraged.
3. In a message construct/message assignment shape, assign the outgoing message by calling an xpath solution.

Here's a sample of the solution that worked for me:

xPathString = "/*[local-name()='Employees' and namespace-uri()='http://mySpecialSchema']";
MsgOutput = xpath(MsgInput,xPathString);