Heh
They are profile fields; You will need to add a new profile field to record user's names
Via the Profile Field Manager, you will add a "Real Name" field, using the settings you wish, then when you goto the Manager screen it will have "fieldX" by it, where X is the number of the field (it varies depending on how many fields you have)...
Then to include them in a post, you add to the postbit_legacy template:
HTML Code:
<if condition="$post['fieldX']"><div>Real Name: $post[fieldX]</div></if>
(replace X with the number from the Profile Field Manager)
Chris