T7400 change of HDD config from SATA over to SAS

I have a T7400 that currently is an all SATA drive configuration.  I want to switch over to a SAS boot configuration.  The T7400 guide says:

I need a SAS interposer and

If there is a SATA drive in the configuration it must be the Boot drive.

The front drive slot can only be SATA drive

If these two statements are not true, I'd appreciate the information.  I have 5 SAS 15K drives, one 450GB and 4 73 GB SAS drives. 

Has anyone done a changeover such as this, from SATA over to SAS, and if so, what were their experiences and if any advice? 

thanks, Ken