Sharing Code base with QTP

As I mentioned before some test automation can be executed via a vbs stand-alone file instead of using QTP. How do you do that without the need of multiple code basis or branches?

The solution (the function getTextFileContent can be found in a previous post):

'************************************
'*** AUT test suite driver script ***
'*** vbs standalone version       ***
'*** by Stefan Thelenius May 2008 ***
'************************************

'Load common functions from library
Execute getTextFileContent("\\server\path\libraryFileName","Unicode")

'Set initial test run option parameter
strRunCode = "intTestRunOptionId = 2" & vbLF

'Load QTP test code
strRunCode = strRunCode & _
getTextFileContent("\\server\path\yourQTPTestName\Action1\Script.mts","utf-8")

'Execute test
Execute strRunCode

Pros:
Faster execution time
Licence free

Cons:
No run-time debugging
Not possible to use QTP features (Test object model...)
Need to implement parameter "TestTool" (If objParameter("TestTool") = "QTP" Then) for all QTP specific code lines, for example using the QTP native Reporter object.

I use it for Web Service testing and some URL bases web testing. Those test can executed via QTP as well using this concept (just change one parameter) so I usally run the test via QTP at first so debugging is possible and when stable I use my vbs-file instead.