External Contact names Visible in Conference


In the conference room widget of user control panel, I can see the contact name of the internal contacts, but when I see the external contacts, they dont appear with the names over there, they just come up as numbers.

How do i make sure that when some one who calls in my conference rooms, I should be able to see their names rather than plain numbers.

I have tried to save their numbers, in the contact manager, as external numbers, but it hasnt worked so far.

When saving i have tried the format with the country code, without the country code, +country code .

Please help in identifying a way.

Thank You