converting vb3 MOD to vb4 MOD

[WorldDomination]

I do not currently have a VB4 forum to use as reference, so it's a bit harder for me to figure out all of the differences and stuff between vb3 and vb4. I want to convert my username images MOD to work with vb4.

This is my postbit code in vb3:
<div id="postmenu_$post[postid]">
<if condition="$show['profile']">
<a class="bigusername" href="member.php?$session[sessionurl]u=$post[userid]"><if condition="$post['field8']"><img src="$post[field8]" border="0"/></a> <else />$post[musername]</a></if>
$post[onlinestatus]
<script type="text/javascript"> vbmenu_register("postmenu_$post[postid]", true); </script>
<else />
$post[musername]
</if>
</div>

All I currently know is that I need to add "vb:" to the tags such as the if/else tags. I don't know what else has really changed, I'm assuming "$post" has changed as well?

This is the username block in vb4:
<div class="username_container">
<vb:if condition="$post['userid']">
{vb:raw memberaction_dropdown}
{vb:raw post.onlinestatus}
<vb:else />
<span class="username guest">{vb:raw post.username}</span>
</vb:if>

Any help is greatly appreciated.