Passing the Description field in "Request a catalog item" workflow

I'm using the "Request a catalog item" workflow to request a Catalog item that deploys a VM. When I manually request this item, I can fill in the number of vCPUs, memory, disk, *and* a Description that then shows up in the vCAC Items list that helps me identify what the VM is used for.

When using the vRO workflow to make the request, I can pass the VM variables - i.e. provider-VirtualMachine.CPU.Count, etc. - but I can't figure out how to pass in the Description. I've tried tricks of looking at the available variables but all I get is this list.

[2015-09-30 11:44:44.775] [I] provider-Cafe.Shim.VirtualMachine.NumberOfInstances

[2015-09-30 11:44:44.776] [I] provider-Cafe.Shim.VirtualMachine.TotalStorageSize

[2015-09-30 11:44:44.776] [I] provider-ExternalWFStubs.MachineDisposing

[2015-09-30 11:44:44.776] [I] provider-ExternalWFStubs.MachineDisposing.vCACHost

[2015-09-30 11:44:44.776] [I] provider-ExternalWFStubs.MachineDisposing.vCACVm

[2015-09-30 11:44:44.776] [I] provider-ExternalWFStubs.MachineProvisioned

[2015-09-30 11:44:44.776] [I] provider-ExternalWFStubs.MachineProvisioned.vCACHost

[2015-09-30 11:44:44.776] [I] provider-ExternalWFStubs.MachineProvisioned.vCACVm

[2015-09-30 11:44:44.776] [I] provider-VirtualMachine.CPU.Count

[2015-09-30 11:44:44.776] [I] provider-VirtualMachine.Disk0.IsClone

[2015-09-30 11:44:44.776] [I] provider-VirtualMachine.Disk0.Size

[2015-09-30 11:44:44.776] [I] provider-VirtualMachine.Disk0.StorageReservationPolicy

[2015-09-30 11:44:44.776] [I] provider-VirtualMachine.LeaseDays

[2015-09-30 11:44:44.776] [I] provider-VirtualMachine.Memory.Size

[2015-09-30 11:44:44.776] [I] provider-blueprintId

[2015-09-30 11:44:44.776] [I] provider-provisioningGroupId

Any ideas on how I can reference and set the Description?

Thanks