[peugeot405]

that is correct.

You add the code

<vb:if condition="$post['fieldxx']">
                                <dt>title</dt>
                                <dd>{vb:raw post.fieldxx}</dd>
</vb:if>

for every custom field, changing the title and the xx to math the custom field you add.

note: the code above is the basic code, there are more extended codes depending on what type of custom field you are using (single-line textbox, multiple-line textbox, single selection radio buttons, single-selection menu, multiple-selection menu, multiple-selection checkbox).

Here are some threads about the subject:

Using your User Profile Fields in your postbit templates
Using your User Profile Fields in your postbit templates (w/ all plugin method)