How to associate Accounts to Custom Object on Creation Import

Summary:

Unable to associate existing accounts to new custom object records

Content (required):

I've been unable to associate accounts when importing to a custom object. I have manually associated an account and then performed an export and there are two fields available to import to, AccountName and AccountName_PartyNumber_c, with the Account Party ID showing up in the AccountName_PartyNumber_c field. When I use that same number to do a new import, the account is not associated.

Version (include the version you are using, if applicable):

22D

Code Snippet (add any code snippets that support your topic, if applicable):