How can I publish an application containing an AWS::Serverless::Function resource with a FunctionUrlConfig property?

I have a SAM template with an AWS::Serverless::Function resource that has a FunctionUrlConfig property. It builds and deploys just fine using the SAM CLI, so the transform clearly works. But when I try to publish it to the Serverless Application Repository (either with sam publish or aws serverlessrepo create-application or via the AWS Serverless Application Repository Console), I get the following error:

Invalid Serverless Application Specification document. Number of errors found: 1. Errors: Resource with id [IiifFunction] is invalid. property FunctionUrlConfig not defined for resource of type AWS::Serverless::Function

It seems like the Serverless Application Repository API simply isn't using an up-to-date schema to validate the template. Since FunctionUrlConfig is part of the documented AWS::Serverless::Function model, it seems like the app repository should accept it. Is there anything I can do to try to get past this? Or do I just have to wait until someone at AWS updates the API's template validator with the latest version of the model?