Using a map is prob best but something like this might work in a batch file....
set d_yy=%date:~10,4%
set d_mm=%date:~4,2%
set d_dd=%date:~7,2%
set t_hh=%time:~,2%
set t_mm=%time:~3,2%
set t_ss=%time:~6,2%
set DtTmStmp=%d_yy%%d_mm%%d_dd%%t_hh%%t_mm%%t_ss%
set FileOut=E:\Mercator6.7\cmgr\mmgr\mail\%DtTmStmp%mi.edi
copy E:\Mercator6.7\cmgr\mmgr\staging\*.cpt %FileOut%