Robot & Selenium Tree Element Expansion - selenium

Question

My supervisor has recently switched us from HP-UFT to Robot with the Selenium Webdriver and I'm finding it extremely difficult to figure out how to use the driver and/or keyword framework to expand a folding tree ul/li webelement.
Below is a stripped out example of the code on the page:
<ul>
<li class="node-class open" id="i1454430045821320">
<a class="" style="" href="">
<ins> </ins>Location Header 1</a>
<ul>
<li class="node-instance leaf" id="i1454430058247421">
<a class="" style="" href="">
<ins> </ins>Location 1</a>
</li>
<li class="node-instance last leaf" id="i14545337159411690">
<a class="" style="" href="">
<ins> </ins>Location 2</a>
</li>
</ul>
</li>
<li class="node-class closed " id="i14544407827351156">
<a class="" style="" href="">
<ins> </ins>Location Header 2</a>
</li>
What I'm trying to do should be extremely simple: I want to expand a specifed closed tree structure if it's classed as closed. Beneath each branch is an optional nested branch, or a selection checkbox. My end goal is to be able to drill down to a location in the tree that the tester specifies and click the end leaf.
Using "Click Element|xpath=/ul/li[a[contains(text(),'Location Header 2')]" does expand the branch but it also selects all of the child node checkboxes.
In UFT, if I hit this kind of problem I'd simply change the parent <li> class to force it open (if I couldn't click or use any of the other methods to drill down and select).
In Robot, I can use the keyword "Get Element Attribute" to READ the class, but I don't see a keyword to CHANGE it so that idea is out. What I'm looking for is a way to expand the tree branches without inadvertently selecting all of the child nodes.
The drilling down through the tree portion I can deal with once I figure out how to open the nodes correctly but opening up the branch without potentially selecting all of the sub-items is making me pound my head into my desk.
I keep thinking that maybe I'm missing something simple. Any assistance on something that I could try would be greatly appreciated.

Answer 1

Figured it out! Thank you all so much for the ideas.
Click Element At Coordinates | xpath=//ul/li[a[contains(text(),'Location Header 2')] | -100 | 0
Luckily all of the ul element columns on the page have the same css style which sets them at 200px width. I figured through trial and error that the "At Coordinates" option clicks from the center of the object (and not the top left as I originally thought). I figured I'd share this in case anyone else ever has a similar problem.