Can someone please tell me how to pin message on a Z10?

This is the wrong section, but you don't PIN anymore. You use BBM.

User Guide

Moved to the Z10 Discussion area.
Obviously no one used PIN messaging as it was removed.

I dont BBM my work colleagues, I only BBM my friends. I was also lead to believe that peer to peer pin messaging was more secure.

BBM is just PIN Messaging organized into conversations. Same thing though.

Correct, and PIN-PIN messages were no more secure than BBM.

Btw: the Z10 is still able to receive a PIN message, however, you are not able to answer to a received PIN.

This is good information. I use PIN messages when I do updates to the BES to alert the users of momentary downtime. It comes in handy. Glad to know that this will still be available.

Cheers for the info, but as I said previously, not all business contacts are not in my BBM list, through their own choice and I cannot make them add me to their BBM list, so it was handy to send a pin message.
I have tried receiving a pin message on my Z10 and it didn't get to me.

Time to change your paradigm. PIN to PIN messaging is a relic. Time to move forward. It happens.

Yep; something else BlackBerry removed from the "old" way of doing things without telling anyone about it. Like BIS, being able to retrieve more than 30 days of messages, being able to sync with your Outlook PIM data and a reliable desktop management problem. ANd shortcuts in a message list to go to the Next, Prior or unopened message.

Time to move but I am not sure it is always forward.

Shortcuts (e.g. press "u" to go to last unread message) might come back with the Q10. This is what I hope.

USB sync with Outlook is coming with a future update but no ETA given except later this year.