First spend the $25 and get the full version of Virtual Audio Cables. Then point the Output of SPL to VAC Line 1, make VAC Line 1 the Input on Breakaway. The audio will feed straight into Breakaway. Be sure you set the Ms per int to 1 on the VAC Control Panel for each cable. If you use an outboard encoder, then you'll use VAC Line 2 as the output of Breakaway and the Input of your encoder.
I highly recommend spending the few dollars on VAC as Win 7 and 8 have buffering and skipping issues with the VAC version that's built-in to Breakaway (Pipelines).
http://software.muzychenko.net/eng/vac.htm