Set visitor messages tab default!

[Hendrizius]

Hey,

We just updated our forums (running 4.2.1 now) and noticed a new feature of vB where users can choose to limit their visitor-messages to Mods and Contacts only.

We further edited our forums to not show the activity-tab anymore.
Now the problem is when a general user gets to the profile of someone who limits his visitor messages no tab is shown. That's why we set the about-me tab as default using the following code:

if (!$vbulletin->GPC_exists['tab'])
{
    $vbulletin->GPC['tab'] = 'aboutme';
}

(hooking at member_build_blocks_start)

What we want to accomplish now is the following:
- If visitor messages are limited, show the about-me by default
else show visitor messages as default.

We tried using the following code for that matter:

if (!$vbulletin->GPC_exists['tab'])
{
    $vbulletin->GPC['tab'] = 'visitor_messaging';
}
else
{
    $vbulletin->GPC['tab'] = 'aboutme';
}

It seems to work just in terms of setting VM as default, but if it's limited, it doesn't show any tab.
Problem apparently is that the tab 'VM' still exists, even though it's limited. It's just not visible thus the php-code fails here.

And this is the reason I'm posting here - Please help me!