Note that you must use a transparent background
Here's the best possible match I can get, in a photoshop file:
Note that it includes the REAL iOS IMAGE (from a screenshot) underneath as a layer, so you can compare.
It seems like VBK wants the single chevron from the UITableView collection. Which is called 'Disclosure Indicator' as opposed to the one available from UIButton which is 'Detail Disclosure'.
I think you want something like this:
It is 50x80 with a transparent background. Use this image on top of a button or UIImageView. Resize it to whatever size you'd like your button to be. Apple recommends a hit target of no less than 40x40. I sized it to 10x16 in my storyboard, but I am using a transparent button overlay so the size doesn't matter.
Image Mirror : http://imgur.com/X00qn0Z.png
Just note however this is not precisely the image used in iOS7. (Nov 2013.) To get the exact image, simply run an app in retina in your simulator, and make a screenshot.