Download Cheat Engine, start CSS.
In CE, select hl2.exe process. Then back in CSS, type in the console "sv_cheats 44875" for example. Back in CE type 44875, select the value on the left, double click it. At the bottom of the windows freeze the value and change it to 1.
And here you go, you just bypassed sv_cheats 1. (Sry for bad english :x)