The syntax for the layout updates depends on the structure of your controller for the admin area.
If you go to your admin menu configuration file (adminhtml.xml or config.xml) you’ll probably see something like this....
Here we can see this menu goes to a controller in folder structure of:
As I wanted it to go to the index action of my controller I didn’t need to specify an index action!
You could loose the ‘controllerfolder’ if you wish, it just helps group the controllers together, if we did action would become:
Therefore your layout XML update handle in my example above (with the folder), it would be:
Handy tip: You can also tell what handle Magento is expecting by looking at the HTML classes applied to the body tag. (just view it in your browser, Chrome for example).
I hope this helps.