Can I implement ScrollToHorizontalOffset() functionality in XAML? (for a dynamic list)

Here's the problem: I have a data-bound list of items, basically a way for users to map a request to a response. The response is an xml-based file. I'm letting them queue these up, so I've used a combobox for responses. The responses will include the full path, so they get a bit long. I want the displayed text of the combobox to be right-justified so the user can see the file name. For my static controls, I just use ScrollToHorizontalOffset() when a file is loaded and I'm done. For this dynamic list, I'd like to do it in xaml.

The "somewhat ugly" solution would be to store all the ComboBox objects as they load... then I can call ScrollToHorizontalOffset() directly, but I'd really prefer to do it a cleaner way than that! EDIT: (Actually, this may not be reasonable. A quick look at trying to hack around this issue gets into some really awkward situations trying to map my datasource items to the controls)

I've tried HorizontalContentAlignment, that only impacts the "dropped-down" portion of the ComboBox.

I've also tried to hook other various loading events, but haven't found one that works.

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