tani's ERFinder is a great tool for creating hak files.
ERFinder is a small tool like the old hak-packer of nwn1. it can open/import/export/save any ERF-formatted files for nwn2, especially HAK, MOD, PWC and ERF itself. it uses OEIShared.dll from your nwn2-installation for all file-io (so it should be placed in your nwn2-folder) and needs .net 2.0 (like all nwn2 tools). it complies to the new ERF v1.1 format, thus allowing filenames to be 32 charakters long (hak-packer from nwn1 only supports v1.0, limiting filenames to 16 chars).
Get it from the vault:
http://nwvault.ign.com/View.php?view=NWN2Tools.Detail&id=9