The only (and the best cross-browser) way as I know is to use an inline-block helper with height: 100% and vertical-align: middle on both elements.
So there is a solution: http://jsfiddle.net/kizu/4RPFa/74/
Or, if you don’t want to have an extra element in modern browsers and don’t mind using IE expressions, you can use a pseudo-element and add it to IE using a convenient Expression, that runs only once per element, so there won’t be any perfomance issues:
The solution with :before and expression() for IE: http://jsfiddle.net/kizu/4RPFa/76/
How it works:
When you have two inline-block elements near each other, you can align each to other’s side, so with vertical-align: middle you’ll get something like this:
Two aligned blocks
When you have a block with fixed height (in px, em or other absolute unit), you can set the height of inner blocks in %.
So, adding one inline-block with height: 100% in a block with fixed height would align another inline-block element in it ( in your case) vertically near it.