HD 500 with EHX Synth 9

[soundchaser 2]

Greetings.  I’m a long time HD500 user, who just purchased the Electro Harmonix Synth 9 pedal.  I use a James Tyler Variax with the Variax digital cable.  The instructions for the Synth 9 suggest that I use the pedal “ahead” of all other pedals in the chain, which I technically can’t do because I’m using the Variax digital cable from my guitar into the HD500.  Any routing suggestions?  Please operate under the assumption that I am an idiot, and explain as simply as possible.  Thanks in advance.