Can anyone explain to me how to perform a coupler conversion on a couple of Bachmann reefers from the rapido style coupler to a Microtrains MT-10 coupler with adaptors? In looking through the instructions I am a bit confused over what to do with the existing coupler spring post. It says not to trim it but not cut it off, but I can not see how the adaptor will fit with out removing the post completely. Any help is appreciated as I am new to n scale.