Agree it was unnecessary hurdle Sony threw up to try to enforce their bloatware. But you beat them at it and now have the cleanest possible install.
When you get Win7 setup like you want, be sure to save externally a Win7 backup image so you never need to reinstall again, just reimage the HD or a replacement using the DVD or Repair CD in 15 minutes.
If you didn't make the bootable Win7 DVD, be sure to make a Repair CD in the Backup Center too. You need this to repair or reimage Win7 if it won't start.