Outgoing NAT-PMP Request to External VPN Provider, Possible?

[planedrop]

Curious if this is something pfSense can do, and if not it would be super cool if it could be added, unless there is something huge I'm missing here.

Probably best to explain a scenario, say I wanted to host a service on port 1234, but I wanted this to be hosted on a VPN providers public IP instead of my own (or maybe I already have a server hosting something on port 1234 for my single public IP and proxying for whatever reason isn't an option), and said VPN provider supported port forwards to clients but only via PMP, i.e. no manual configuration for this.

Is there any way to use pfSense to periodically send PMP requests to the VPN provider so port 1234 stays open and forwarded to the pfSense's "LAN" IP as a client?