How to Change HX Stomp Presets with a Boss RC-500?

[paulsmusic]

I've recently started using an HX-Stomp with a Boss RC-500 loop-pedal, and want to use MIDI to sync preset changes between the two devices. I've set the RX / TX MIDI channels to 1 on both devices, and am using the RC-500 to send Program Change messages to the HX-Stomp. I've read the manuals for both devices, and made the appropriate settings (I think!!), so that when I change presets on the RC-500 it should also change presets on the HX-Stomp. It's not working though...

As far as I understand, the RC-500 automatically sends a Programme Change message when I switch presets, corresponding to the patch number. So if I switch from RC-500 Patch 1 to Patch 2, it automatically sends a PC:002 message, which should change the HX-Stomp to preset 2...or have I misunderstood this?

I'd be really grateful for any advice. This is my first attempt at using MIDI to sync devices! The only other problem I can think of is that the cable I'm using might not be suitable; I didn't buy the official BMIDI-5-35 cable recommended in the Boss manual, but purchased (new) a similar cable on Ebay for 1/3 the price...