create a custom step in checkout

Hi, this is Marco from Italy.
I'm usign drag'n drop CHECKOUT_WORKFLOW_EDITION.
Have placed a "Fields" step in my workflow and it appears correctly in the right place in the progress bar.
On front end, going on step by step when arriving there i see a clear page.
How can i populate from administration that step with a form requiring some fields of mine? (p.e. some new fields about billing address)?

If i add fields in "default fields" theese ALL go into the login request.
Is there a way to say to hikashop put theese required fields in a new step?

Thanks in advance,

marco