You need the CRC32 of the unpacked client to match the one of the real client. Look here to find out how: https://www.mpgh.net/forum/164-combat...ass_stuff.html
However, that tutorial won't work to get rid of HShield anymore. Apparently, HShield initializes Combat Arms's Direct3D, so getting rid of it won't let Combat Arms start (thanks iSecks). Not sure why you'd want to play with an unpacked client, anyway. It's not like playing an unpacked client gives you any benefits.