I have taken and outcommented the following code from the template "post" in "Topic View":
<if test="postMember:|:$post['author']['member_id']"> <span itemprop="creator name" class="author vcard">{parse template="userHoverCard" group="global" params="$post['author']"}</span> <else /> {parse template="userHoverCard" group="global" params="$post['author']"} </if>
I then changed the code to be compliant with the userInfoPane template:
<if test="postMember:|:$author['member_id']"> <span itemprop="creator name" class="post_author author vcard">{parse template="userHoverCard" group="global" params="$author"}</span> <else /> {parse template="userHoverCard" group="global" params="$author"} </if>
And i've put it in the template "userInfoPane" under "Global Templates". Add it after these lines:
<span class='hide' itemprop="name">{$author['members_display_name']}</span> <ul class='basic_info'>
Then i've added id="postusername" after class="author vcard"
In ipb_styles.css i have added this at the bottom:
#postusername { font-size: 12pt;}
I hope this answers your question.