David,
We developed a system to get around this limitation using WinRM. We were in a situation where we'd need to save a generated password and/or retrieve password from PMP on newly deployed servers. Since they were new we couldn't have an authcode previously generated for them. Our PowerShell script connects to a central server using WinRM and then executes the REST API call to PMP. This way we're able to use the single authcode for that central server. Obviously there's a few risks introduced by doing this but we've greatly restricted the users that can connect to that server using WinRM and also reduced the IP ranges that can connect it using WinRM. Furthermore we've limited our API account to only be able to view a select few accounts in PMP.
Adding this modification to our scripts for use from a single host was fairly easy. Being on a domain is also very helpful.
-Chris