I attempted to do this. At first I was getting the message:

This action has been automatically identified as harmful, and therefore disallowed. If you believe your edit was constructive, please inform an administrator of what you were trying to do. A brief description of the abuse rule which your action matched is: New editors cannot create pages

This appears to be due to the abuse filter:

<abusefilters>
<filter id="1" description="New editors cannot create pages" pattern="user_age &lt;= 128400&#13;&#10;&amp; old_size === 0&#13;&#10;&amp; action === &#039;edit&#039;&#13;&#10;&amp; user_editcount = 0" />
</abusefilters>

In order to not be a "new user" it appears that you have to have made at least one edit in the LessWrong Wiki. I'm far from convinced that the LW Wiki actually needs an article on quantum mechanics, but it's got one now. I then managed to successfully create a wiki page.

With that being said, I'm still unclear as to how to make my LessWrong profile link to the Wiki. My user page http://lesswrong.com/user/leplen/ still redirects me to http://lesswrong.com/user/leplen/overview and there is no obvious reload from wiki button.

Overall I would rate this process moderately difficult and surprisingly time consuming. If this is something that anyone expects a significant number of people to do, it might be worth it to make it easier or write a guide.