You can simply drag the Skype icon from your start menu to the quick launch and drop anywhere between the icons already there.
You can right-click on Skype from you start menu and select "Add to Quick Launch". If you don’t see “Add to Quick Launch”, just hold the Shift button on your keyboard while right-clicking on the Skype to make the option show up.
For faster access to Skype you can also try "Pin to Start Menu" right clicking on Skype from your Start Menu. This will give you short cut to Skype as soon as you click and open the start menu.
Don't worry about this problem. You have to do simple two steps and your problem will be resolved and this problem not relates to windows vista with service pack 2. You can copy Skype icon into 'startup' (locate in start / program / startup) and when you start your window, you Skype automatically run and you don't need to press a icon in quick launch bar.
Two steps for creating icon in quick launch bar :
Drag your Skype icon into desktop or right click on your Skype icon and send to desktop as shortcut.
Drag this desktop into quick launch area. its so simple dear.