yeah I totally recomend dealing directly with the registrar and not using the control panel from the hosting company. Because ultimetley I doubt the registrar cares where the domain is pointing while a host might want you to use there setting in hopes of using them to host.
You cannot go to the registrar in this case (and I would say in any case), because they are using AAAQ, which is for wholesalers only (HostWay mainly).
And if I understood Hurga's statement, then no... you cannot go to NetSol to update/change/register name servers unless the domain was registered through them.
HostWay is not so good when it comes to "domain only" support. I had a bad experience with them try get a domain transferred out of them. It took me two weeks and several mails to finally execute the transfer process.