I've not figured out how to do this, however, depending on what you want to do I have figured out a simple workaround for parsing things like images in the postbit.
The basic thing to remember is, that whilst things
within the custom field won't parse (either BBcode or HTML), HTML on the template
will parse. So, for example, whilst you can't make an image display by having:
Code:
{vb:raw post.field5}
in the template and
Code:
[im]http://www.example.com/myimage.gif[/img]
in profile field 5, you CAN generate the same effect by having:
Code:
<img src="{vb:raw post.field5}">
in the template and
Code:
http://www.example.com/myimage.gif
e.g. what I was doing on my site was allowing permitted users to have space for an advertising banner above their signature, which is in the template as:
Code:
<vb:if condition="$post['field5']"><a href="{vb:raw post.field6}" target=_blank><img src="{vb:raw post.field5}"></a></vb:if>
which allows them to input the URL of their banner image into custom field 5, plus the URL to their site in field 6, resulting in a clickable banner when parsed in the postbit.
Don't know if that helps you at all...