Here's an example using the vlax class.
Sub test()
Dim vlax As New vlax
Dim strText As String
strText = "Hello there!"
vlax.SetLispSymbol "test", strText
End Sub
Running the above will allow the symbol "test" to be used in a lisp function. Typing !test at the command line yields this:
Command: !test
"Hello there!"
HTH,
Jeff