DCB,
Yes, no problem to FSX.
FSX ac mdl's have several important diferences. An FSX mdl, well in fact, you have to have two. One for the ac, and one for the VC. So even if you could convert each to an Fs2004 mdl , you would have to combine the two, to have an Fs2004 ac with a working VC.
The main problem is the format of the mdl, which is not compatible with Fs2004, and cannot be converted with MDLC. Also FSX mdls usually exceed the 65,535 mdl poly limit of Fs2004, so again this will affect direct import. Although you can import into MCX, it won't export to Fs2004 due to exceeding that poly limit. With FSX scenery, you may have better luck.
Basically FS2004 and CFS2 mdls are the same but have different file headers, also the animation tables have differences in their assignments. So when converting, MDLC basically changes the header, and nulls or re-assigns some animations.
Wulf,
I would construct with Blender, output as a .3DS file. Import into MCX 1.4, then output as an Fs2004 mdl or bgl. Then convert to CFS2 using auto mk_MDLC or manual MDLC.
Below is a simple object (no animations) from Blender, out-putted as a .3DS file. Imported into MCX and out-putted as an Fs2004 mdl, then converted with mk_MDLC for CFS2, and flying in CFS2.
Cheers
Shessi