For Developers: Outflow Valve modelling question

Good afternoon,I am going to go ahead and finish my SkyEurope textures set (first livery, OM-NGP, in almost finished state, can be found in avsim library, dated January 12)However, I ran into a little detail,your model does have outflow valve with old-style cover. I was pointed to the fact, that all SkyEurope NGs, as well as all newer bulit NGs (from approx 2003) sport a newer modification, that has the outflow valve cover with "teeth".Is it possible to alter the appearance, for example by use of alphachannels, or is this look definitive?Reference: http://www.b737.org.uk/pressurisation.htm#Pressurisation_Valves