But as far as I can tell, that information is already there.Looking at the RSS feed for dw_suggestions (http://dw-suggestions.dreamwidth.org/data/rss) I see the following in the data for this entry:

<lj:poster>ratcreature</lj:poster>

and for the Atom feed (http://dw-suggestions.dreamwidth.org/data/atom):

<author>

<name>RatCreature</name>

</author>
<dw:poster user="ratcreature"/>

Perhaps the problem is in what the recipient site expects, not (or not only) what Dreamwidth provides?