I just saw that those links are generated with javascript, probably with a widget, so it is indeed not easily possible to change the name of the div container.
I had not thought about this - Alternatively you can give the div.rss-box a second width if it is inside a post:
Paste the following into the textarea "CSS Inserts" at the menu tab "HTML/CSS Inserts"
HTML Code:
.post div.rss-box {
width: auto !important;
}
If that doesn't work try this instead
HTML Code:
.post div.rss-box {
width: 100% !important;
}