Which camera are you shooting with?
If it's with an M8 then you'll have to have the lens flange coded if you want the focal length to appear in the EXIF and the camera to perform any adjustment due to nodal point and rear element distance from the focal plane. Since you're using a 25mm ZM, it shouldn't be an issue at all if you're using an M8.
If you're using an M9, the wide angle lens *may* give a bit of colored vignetting but I don't think it does at all. My 21mm f/2.8 ZM never did on the M9 as I think these lenses are retrofocal enough to keep the light from causing colored vignetting. Anyway, if using an M9 with the 25mm lens, select the closest focal length in the menu with the f/2.8 aperture. Either 24 or 28mm. You could probably try the 24mm f/3.5 as well. There is no way to actually code in a 25mm lens so you'll just have to live with this issue. The 50mm would probably be best represented by the 50mm f/1.4 pre-asph.
If you want the camera to detect the lenses, you'll have to get the flanges coded then you could set the lens detection to auto and it will load the EXIF as well as any corrections automatically. If you don't get the lenses coded, then you'll have to choose the lens being used from the menu.
The lens coding detection or selection from a menu in the M9 affects only the EXIF data and the vignetting profile for lenses wider than 50mm. It does not have any effect on the framelines in the viewfinder. That is selected by a mechanical linkage between the lens locking lug and the camera.
Phil Forrest
