Bi-directional k-bus to CAN

I am trying to adapt k-bus 10-12V signal and put the constituent TxD, Rxd
through a Max232 and then a PIC18F2XX. MY Final Goal is to convert K-bus to CAN_H and _L. Up to now, I figured I should use something like a 'single ended bus transceiver' AT6812b, or SI9243AEY to break apart the K-bus into Txd and Rxd. I think I must be missing something obvious though since these aren't easy to find bits. Can I push the K-bus all the way though the Max232 and on into the PIC, or do these devices require the symmetry of signal processing I think they do. The application is Automotive.

Thank you

 

I found a nice bridge in a Dalllas Maxim DS2480B, its a little pricey though.
Onward

Thanks