SMS-draft on incoming call

I have a tiny problem with my Android on HTC Wildfire. When I got incoming call and my screen is blocked, I have to move a ring to unblock and answer the phone; but if I move this ring fast enough and my phone doesn't capture my movement, I get a cancelled call and a sms-draft 'Sorry, I'm busy' etc. The problem is: is there any way to disable this option to have an sms-draft? I'd like to have not a possibility to slide to sms-draft with call cancel. My Android version is 2.3.5