XF 1.4 Profil Members - only text not link

I would like to disable the linking of profiles on the forum ( avatar , lastposter etc. )
If I'm not mistaken , the current display of links used

<xen:username user="xx" />
<xen:avatar user="xxxx" />

How to make it to be displayed only nick without link and avatar without link

I see that I need a new function helperUserNameHtml

currently is : Produces a <a href="members/username.123" class="username">Username</a>
and I need : Produces a <p class="username">Username</p>
How to do it? I need to write a plugin ?