Hello jetblack,
A DIAdem .TDR file does not contain data or variables, it only contains report layout information. However, you can create and modify DIAdem report layouts programmatically in your VBScript code. Attached is a small example of creating a DIAdem report layout in VBScript, and you could extend this to save user-entered variables to the different parts of the report layout (axis labels, legend, etc).
David Mc.
NI Applications Engineer