Lesson: integration and playing friendly with others is huge for B2B.
Love it. We've had a few moments like this at Paydirt (http://paydirtapp.com/). As engineers, we tend to have hangups about little details like this that customers genuinely don't give a second thought to, and they can be a means to massive (and multiplicative!) business wins.
Example for those who have never been on the site before: http://charliethemost.bandcamp.com/
Kudos, keep it coming!
edit: http://snag.gy/FNBUs.jpg (using chrome)