How do I manage where I store my music on my enV touch?

I want to put more music I just recently downloaded on my phone. When I buy music from iTunes, I synch it to Rhapsody, and from there plug my phone into the USB and usually it'll say LG VX11000 in Rhapsody. Today, it didn't though, and I realized that my phone itself said the music would go to my memory card, but when Auto play came up, it said internal memory. How do I switch back to my music going to internal memory to lat me get some more songs on my phone? Thanks! =)