This is very surprising. I haven't come across a BDP that does not have analogue (RCA) output. If indeed, the BDP-450 does not have analogue output, then you have the (costly) option of going via DAC.
Does your amp have HDMI or Coaxial or Optical? Then you could use that also.
Pioneer BDP-450 review - Blu-ray Player - Trusted Reviews
check the above link, it clearly says no analogue audio output.
Actually i was considering this pioneer bdp 450 and panasonic bdt 220. The Pioneer dont come with analogue output and i dont think my amp marantz pm6003 has any of hdmi/coaxial/optical, so i dropped the idea of pioneer.
Regards, Amit