Its a very easy way to get this.
Download AVIDEMUX (freeware, no codec pack is necessary): http://downloads.sourceforge.net/avidemux/avidemux_2.6.0_win32.exe
Install, run and load your .m2ts file. after this, only set like screenshot above:
Save this (added extension automatic)...2,3 seconds after and finished. Get your file full compliant for desired video editor. NO CONVERSION WILL MAKE.
Tested using: Vegas 10, 11, 12, Cyberlink PD 9, 10 and 11, AVS Editor 6.2, Adobe Premiere CS6, Corel Video Studio X5.