Can't see my purchased items after changing my Costa Rican store to US Store

I've been purchasing music from Costa Rican' Store for 6 months now and have more than 800 music and few Apps purchased. Recently, I changed my store to US Itunes, however, I cannot see my purchased items on the PURCHASED section of my Itunes. I could see though receipts though of those puchases but not the actual list where I could click the download link of the song/App. What can I do? Please help!