Security of Sony Ericsson K550i

[Udaya Maurya]

I'm unable to lock my phone's keypads with a security code. I guess that the facility is not available with the model. How can I do so, is there any external software which can do so?

i want to lock my certain folders like messeging, settings etc.

[a_k_s_h_a_y]

not possible in any SE phones
else take the flashing way and apply patches.

[Udaya Maurya]

a_k_s_h_a_y can you precisely tell what patch I need to download and from where?