Changing lease based on the custom property as soon as end user place a catalog request in VRA 7 with EBS

I have a requirement to set the initial lease based on the custom property such as  if company.custom.env= prod { set __Cafe.Request.VM.LeaseDays = 365} else if company.custom.env= eng { set __Cafe.Request.VM.LeaseDays = 65}

But i got stuck in updating this hidden properties run time ,  Please let me know if you have some idea to update a hidden property using vRO workflow

#vRAVmProperties.get("__Cafe.Request.VM.LeaseDays")