Here is my scenario:  I live in the US and have a US PlayStation Network (PSN) account.  I've bought from this on several occasions with no hassle at all.  Additionally I have PSN accounts for the UK and Japan setup on my system so I can browse their stores and checkout demos/videos that might have not come to the US store yet.  I haven't had the desire to purchase anything from either the UK or Japan store up until now.  My friends and I have been playing quite a bit of SingStar as of late and I wanted to pick up some additional songs to fuel the fire.  The UK store has about twenty songs on that the US store does not that I would like to purchase, though my credit card is invalid on the UK store.
So, Here is my question:  Has anyone had any experience with purchasing from stores outside of their region?  I've spent some time perusing Google for an answer and most of what I find are threads asking the question with no clear answer, so let's hope to break that trend here.  
 
Thanks for any help.  Not often do I find a company who doesn't want to take my money!  
