I am using a lexicon lambda with cubase le. The front of the lambda has an input labeled "instrument". I figure this was a good place to plug in my acoustic guitar. Problem is, the recording only comes up on the left channel, and I can't find a way to record through this input, and have the same track on both left and right. I set up my other instruments through a preamp with the L and R outputs connnected to two different inputs on the lexicon.
Any ideas on how to get this track onto the right side, or is this input unusable?

Thanks!!