To split your signal, be sure to use no mono FX blocks in the PRE amp position of the HD500. Pan the two channels hard left and right in the 'mixer' on the HD500. In the HD500, for routing purposes, assign channel one to guitar only, and assign channel two to XLR in only. When you send that signal via USB to the computer, you should be able to arm your recording software with two mono tracks, and assign the left HD500 to one track and the right HD500 to a second track.
When placing mono fx blocks in the pre-amp position, all signals are merged. When there is a stereo fx block or none in the pre amp position, the two channels are left separated.
-----from the manual-----
Page 3, Setup: Input Options
Input 1 and Input 2 Source (Knobs 1 & 2) - Select the physical input(s) that you want to be the “source” fed into the signal path. Note that you can choose different Sources to independently feed each signal path, or choose Same to feed a common Source into both paths.
About Source Input Signal Routing:
It is important to note how POD HD500 actually routes Source Inputs 1 and 2 through Amp & FX Blocks that are positioned “Pre” position. The following behaviors apply:
• In a configuration with no Amp or FX Blocks in Pre, Input 1 is fed only to Path A and Input 2 only to Path B. Therefore, this is the best configuration if you want to retain discrete Input Sources into Paths A & B.
• Placing an Amp Block or an active mono FX Model in Pre results in a “mix-down” of Input Sources 1 & 2, feeding the same, combined signal into each Path A & B.
• Placing a Stereo FX Model in Pre results in the left channel FX output being fed to Path A and its right output to Path B.*
• The Mixer Block’s Volume and Pan options provide independent control for Path A & B outputs before they are fed through any Blocks positioned “Post” the Mixer.
• By setting Input 2 to “Same,” this effectively routes your Input Source to both stereo Paths A & B (which is how you can feed one guitar input into two Amp Models and/or parallel FX, for example).
Model Types and Mono/Stereo Signal Routing
It is important to note that some Models (all EQs, Wahs & Volume, and some Modulations, Filters, Pitches and Delays, as well as the FX Loop) preserve a stereo output within the signal chain, while others (all Dynamics, Distortions, all Amps & Preamps, and other various Models) are mono FX and do not. The POD HD500 Inputs 1 & 2 are fed into the signal chain as stereo (see “Page 3, Setup: Input Options” on page 2•4).
Therefore, wherever a mono FX or Amp Model is inserted, the Left & Right channels of this stereo signal is “mono-ized” and heard as a two-channel mono signal at the Model’s output. To follow are a few examples: