Solved
How do I set a Lead's ForeignSysPersonId value via SOAP?
The SOAP API docs hint at a ForeignSysPersonId variable that I can use for Lead keys created by an outside system.
But how do you set that value? I cannot find a form field that looks like it corresponds to this, and Marketo ignores it when I try to set the attribute "ForeignSysPersonId" in a Lead through the API.
But how do you set that value? I cannot find a form field that looks like it corresponds to this, and Marketo ignores it when I try to set the attribute "ForeignSysPersonId" in a Lead through the API.