Hi Scott,
The isl file settings override any settings in the application, by default. It has to, because otherwise, app styling wouldn't work on any existing application.
You can change this by setting the ResolutionOrder property on the ComponentRole in the isl. But this isn't likely to be something you want to do.
So there's really no way to do this for one specific color setting on one specific control. You can use the UseApplicationStyling property on the UltraPictureBox to turn off AppStyling for a snigle control, but it applies to the whole control, not just the borders. Similarly, you could use the StyleLibraryName or StyleSetName properties to apply different settings to a particular control.