Bootstrap 2.3 Responsive Navbar align-right

Bootstrap 2.3 Responsive Navbar align-right

Learning Bootstrap (and frontend-stuff in general) recently and am stuck
at one particular problem. I have a navbar that scales across the whole
pagewidth with a logo aligning to the left and then a followup of 5 items
in an unordererd list, floating to the right. Works great as long as the
responsiveness doesn't kick in. The general behavior showing when entering
a certain min/max width - ordering the list-items underneath each other -
is great, however, the right floating is lost somewhere down the road
then. While skimming through the bootstrap-responsive.css I have trouble
spotting the line responsible for this behavior. Does anybody have any
idea where I should start looking?
<div class="navbar">
<div class="navbar-inner">
<a class="brand" href="#"><img src="img/logo.png"
alt="horizontal-ad"></a>
<ul class="nav" style="float: right;">
<li><img src="img/ad/adhorizontal.jpg" alt="horizontal-ad"></li>
<li><img src="img/ad/adhorizontal.jpg" alt="horizontal-ad"></li>
<li><img src="img/ad/adhorizontal.jpg" alt="horizontal-ad"></li>
<li><img src="img/ad/adhorizontal.jpg" alt="horizontal-ad"></li>
<li><img src="img/ad/adhorizontal.jpg" alt="horizontal-ad"></li>
</ul>
</div>
</div>
Besides the inline-styling of the unordered list, the only rule I override
is .navbar-inner from the main bootstrap.css to adjust the coloring.
Regards!
::edit: I just realized that this has nothing to do with the
bootstrap-responsive.css, since I removed it but the behavior remains the
same. However, the problem still exists. ::