After much Internet searching, I've finally stumbled (on myself) upon a cure on searching for the P2P folder.
Recently purchased a DNS-320L NAS. Updated to latest version 1.03b. Installed 2 x HDD which appeared as Volume_1 and Volume_2 when Windows network map (Explorer). I've made 2 x network map to the two mentioned volumes. Downloaded a torrent as a test and could not find the completed files although the P2P app shows 100% completed. Contacted DLink support but they offered little help.
While I was on the phone with the support guy, I found that I was able to do a 3rd network map as //NAS-IP/P2P and suddenly all the files appeared in front of my eyes !!! So be aware that mapping to the root Volume folders won't make the P2P folder appear. You'll have to do a 3rd network mapping.
Hope this helps someone else out there for it took me a while to find this information