SSAS: Custom format string for “duration” using MDX

I recently struggled with the following challenge in Analysis Services:
In one of the fact tables there was a field duration which actually was a duration of a certain status in seconds. I needed to display this in a readable format, like "2 days 22:15:59".

bing brought me to the following great article, where Mosha explains how you can use MDX to create a custom format:
http://sqlblog.com/blogs/mosha/archive/2008/09/26/displaying-duration-values-mdx-expressions-in-format-string.aspx

When you apply this for a calculated member you get something like this: