You can press <TAB> while the splash screen is showing to display the POST screen. There is no BIOS setting to force POST display, but there is one way to make it show the POST screen all the time.
You need to hack the BIOS file and remove the splash screen images. THIS IS VERY, VERY, VERY DANGEROUS, not to be done by the faint of heart/non-technical, and can render your computer a brick! With that said, I have successfully removed the splash screens from my three shuttle systems, SB61G2V4, SS21T, and SD11G5.
Another treat for SB65G2 owners. 007 bios with picture no intel logo
disable BIOS splash
Go read the above threads. Basically, you use CBROM to release the splash images from the BIOS file, and then reflash the computer with the hacked BIOS. If you do this incorrectly and brick the computer, it's not my fault.