How to draw line in DataField

Hi all,

I need to draw a simple vertical line in the middle of a DataField I am building. 

How can I do that?
Is something I need to define in drawables.xml and/or layouts.xml files? 
Or is something you have to do directly in Monkey C code with DC object? 

I tried different solution I've found here on the Garmin Forum but nothing seems to work. 

Thanks for helping me.