How to add a dialog for additional input from user during infrastructure vm provioning?

I’ve been playing with MIQ for a bit now and have learned alot about automate, provisioning, etc… We have a customized provisioning profile and have it properly configured so users get that dialog when going through the infrastructure vm provisioning process. I’d also like to some how call a custom made service_dialog to add additional data to the request before the miq_provision_task is created.

Mainly I’m trying to use the Chef service_dialogs to assign a chef role so the chef_bootstrap method has a role to use when bootstrapping the new machine as one of the VMProvision_VM state machine steps. I know I can add fields by hacking the appliance files but am trying to avoid that for ease of future upgrading.

Is this even possible?