Actually I was able to add OutlookBarItems to OutlookBar in VS's designer. This is what I did:
I downloaded the 14.05 binaries
In the General tab of the Toolbox, I right-clicked and selected "Choose Items".
In the window that appeared, I selected the "WPF Components" tab and then clicked the "Browse" button.
I navigated to where I have downloaded the 14.05 binaries and added both Telerik.Windows.Controls.dll and Telerik.Windows.Controls.Navigation.dll
Once I hit the "OK" button, the controls appeared in my toolbox.
Then I dragged an OutlookBar control onto the design surface and from its property grid I selected the Items property.
When the Collection Editor opened, I was able to add an OutlookBarItem.
Could you please let me know whether these steps work for you? If not, let us know so we can assist you further.
the Telerik team
Do you want to have your say when we set our development plans?
Do you want to know when a feature you care about is added or when a bug fixed?
Telerik Public Issue Tracking
system and vote to affect the priority of the items.