hb-callout-box padding and height

I made the .hb-button inside the .hb-callout-box bigger.

So far, so good.

However, the padding seems to pad only the text, and the larger button is not centered anymore, even though I have vertical-align: center !important; on everything in there.

Changing the padding doesn’t work, because it remains padding around the text, but not around the button, which has more height than the text. Here is a picture:

http://i64.tinypic.com/qz5ett.png