ICQ/Aim in Memberlist

What do I have to do to get AOL/ICQ/YAHOO to show up in the memberlist. I uncommented the relevant sections in $memberlist and $memberlistbits but nothing shows up in the AOL/ICQ/YAHOO columns

<td bgcolor="{secondaltcolor}" align="center">$icq</td>
<td bgcolor="{firstaltcolor}" align="center">$aim</td>
<td bgcolor="{secondaltcolor}" align="center">$yahoo</td>

That doesn't work as uncommented, what does?