I have downloaded sdk_2.1. At the link nokia call it V2.1,Borland&Microsoft but when I unzipped it the name is C:\126 Series 60 v2.1 Final DOT NET 03.06.2004 0840
Anyway, the borland editor asks my for pathes and things of the new SDK which I don't know how to set...
basically with borland, you could use SDKs for MS as well, but then you need to have MS tools installed into the PC as well. I at least got them when installing the BuilderX, so check the borland documentation for more information.