forgot my security cody in my HTC mobile

First, you could try the  #UNLOCK#  command;  

1. Send SMS with the following message to your device: #UNLOCK#  Edited: (#UNLOCK# would only work if you send it from your Trusted Number.)
2. Your device sends the reset SMS message with instructions to the trusted number.
3. Send the reset code from the trusted number to your device.
4. Your device is unlocked and you can create a new security code.

If this does not work you have to open a support ticket with F-Secure; http://www.f-secure.com/en/web/home_global/support/contact/request

Relevant past threads;

http://community.f-secure.com/t5/Security-for-PC/f-secure-mobile-password/m-p/11397#M2688

http://community.f-secure.com/t5/Security-for-PC/Forgot-lost-your-security-code/td-p/7439