Accessing an element defined in a style's template in wpf?

Question

I have a wpf tab control which I added a scrollviewer to. This is all wrapped into a style which is situated in a resource dictionary.

Now, on the window's xaml side, all I do is set .

I would like to access the control viewer element, as defined in the style as follows:

<Style x:Key="MyTabStyle" TargetType="{x:Type TabControl}">

.......

How do I access the scrollviewer which is so deeply nested in the heirarchy?