Well, I came across a great deal on a Surefire Millenium Forend light system, but found out that it is the one designed to fit into the round handguard cap, and I have the triangular h.g. cap on my BM Dissipator.  Considering the deal I got on the Surefire, I am thinking it would be better to try to switch out the handguard caps than this one up.  My question is...  Is this a process that a mechanically inclined individual can do?  What are some considerations that I should take not to have to replace the front sight assembly (from a brutal mauling) after I get all said and done?  Any suggestions to links or other references would be appreciated.  Thanks in advance.....dave