Adding Facebook Icon to Postbit

[s0lidgr0und]

I'm looking to add a link to my postbit legacy to a member's Facebook account. I've seen the modification for this, but it seems more involved than it really needs to be. I looked at the postbit legacy template and found the portion of the code where the other icons are listed. It looks like it could be added a lot easier.

Here's the piece of code I'm looking at:

<div class="imlinks">
{vb:raw post.icqicon} {vb:raw post.aimicon} {vb:raw post.msnicon} {vb:raw post.yahooicon} {vb:raw post.skypeicon}
</div>

Now for each of these references to the icq, aim, msn, and other icons, where are they being referred from? I'd like to simply be able to add {vb:raw post.facebookicon} to this part of the code, but what's the other part that I'm missing? Obviously, it must be referring to the image file and also a url, but beyond that I'm lost.

Thanks for any thoughts.