From what I understand of your question, you want to use the Line 6 Toneport USB Interface to record on ProTools LE Software... Am I right?
If this is the case... then you cant do this. To use the ProTools software you have gotta get a Digidesign or an M-Audio interface. But the advantage of this is that once you have for example, a M-Box, you can then not only use ProTools LE, but also LOGIC, Reason, Abelton, etc... via Re-Wire.
Hope this helps...