you would need records of the type
mydomain.com IN NS mydyndnsname.dyndns.com
in the .COM name servers. I doubt that you can do that. the rules for those name servers are that you need two and they need to be fixed. (BTW, zone-edit might be of help try to read there)
www.zone-edit.com, then you can update the records yourself...
BTW the biggest problem will be the tmeout on records you need all A records to have a short Cache Time To Live and DNS server managers don't like a lot of request is it is not realy needed...