How to change the the border color for SelectItem

I am using SmartGWT power edition 4.0.
I want to change the SelectItem border color to red. If I set it using FormItem.setTextBoxStyle(redStyle), the border doesn't include the pickup icon. If I set it using FormItem.setCellStyle(redStyle), the border is bigger than the SelectItem. Which API should I use to set the item border style?