Delegate cannot create online meeting on behalf

Lync is designed to be used as a complete platform for communications, including instant messaging and voice over IP, so this feature will have some problems when being used for people enabled only for PC-to-PC communication as the delegate settings are on a page shown only for users enabled for enterprise voice.

1. First you must enable the user for Enterprise Voice on Lync Server Control Panel: 
2. Start > Programs > Microsoft Lync Server 2010 > Lync Server Control Panel 
3. On Users tab, search for the username, double-click the user's record in the results pane 
4. On Telephony, select "Enterprise Voice"
5. Click Commit 

Then, after waiting about 1 hour for full propagation the user's Lync client will have the Call Forwarding Settings page and on user's computer, you'll need to follow below steps:

1. Expand the menu, Tools > Call forwarding settings * 
2. Click Edit my delegate members 
3. Click Add… 
4. Find the user you want to grant delegate rights 
5. IF you want your delegates to receive calls on your behalf, check the box under Receive calls and select your preference on “Ring your delegates after this many seconds”. Otherwise, uncheck the box under Receive calls. 
6. Click Ok; Click Ok. 

* If the user doesn’t have the option Call Forwarding Settings, restart the computer and try again.