I'm creating a Custom Object in Marketo and want the custom objects to be associated to the Marketo Person/Lead. I would like to link this custom object to the Person/Lead using the "SFDC Id" field which is a GUID from Salesforce. The SFDC Id field is available and accurately populated with the Salesforce record Ids on the Person/Lead, however, this field is not available as a link field in the Custom Object when I'm attempting to map it. There is an "Id" field available for linking, but I think that's referring to the Marketo GUID - this field is not listed in field management so I'm unsure.
Am I missing something here, or is this a limitation I'm experiencing with Custom Object linking.