Form delegateSubmit migration question

Hello All,

I'm trying to migrate project from Wicket 1.4 to Wicket 6.

previously Form.delegateSubmit was Form.delegateSubmit(
IFormSubmittingComponent
<http://ci.apache.org/projects/wicket/apidocs/1.4.x/org/apache/wicket/markup/html/form/IFormSubmittingComponent.html>
submittingComponent) and the code:
submittingComponent.getInputName() worked as expected
right now it is: Form.delegateSubmit(IFormSubmitter submittingButton) and
it is impossible to get inputName anymore :(

I tried to cast submittingComponent to IFormSubmittingComponent but it is
not working due to submittingComponent is of type
"org.apache.wicket.ajax.form.AjaxFormSubmitBehavior$1 [ at ] 33b88671" and I'm
unable to cast it to something useful :(

Thanks in advance!