Any way to start a Perforce Personal Build from the REST API?

We are able to run personal builds with a Perforce Changelist unshelved, using the ‘run as personal build’ check box and then the ‘Shelved changelist ID’ field in the Team City UI dialog.  But is there any way to do it from the REST API?

When I look at the parameters on a build made using the dialog, it looks like there's a property ‘personal’ set to true, and also two properties ‘vcsRoot.<>.shelvedChangelist’ with the value of the CL, where <> is 1 and our project vc root name.  

But if I try to set those properties from REST, it does not result in the CL being unshelved.  Any ideas?