PerX is better but I'll still tell you how to do it.
1.Go to Set Process and type in "Engine" without qoutes.
2.Click add and select the hack dll.Tip: always place hacks in your desktop it is easiest to find.
3.Go to setting and select Automatic (this will automatically inject the hack into Combat Arms.)
4.Then you should select "Close after Inject".
5.Start Combat arms. If i doesn't work just PM me and I will try to help.