Phone lock down. Block calls not in contacts via pin?

[veedubguru]

Someone at Sprint told me that this feature is easy to enable since most businesses do this to prevent employees from making personal calls on the work phone.

The phone I'm wanting to do this on is an 800W. It's my kids phone on our business account. He's placing calls to numbers he should not be calling. Rather than taking his phone away, as I need him to be able to call me and visa-versa, I want to employ this lock. Supposedly it keeps the phone from dialing numbers that aren't already stored in contacts, or editing / adding of contacts, and hard resetting. The default pin for this I was told is the last 4 digits of the phone number. I'm hoping it will prevent texting even though that stupid Palm has a non-windows texting utility... so who knows.

Anyone know how to do this? Any help would be appreciated.