Computer: Dell Precision M4600

HDD: 500 GB

MY QUESTION:

I would like to use a SSD-disk to be the master (bootable) hard disk (for the system) using the WWAN slot as choice #1 (whit a mSSD-disk) or, if not possible, the DVD location (with a hard disk cabinet and a normal SSD) as alternative #2. The original HDD will be used just as a data hard disk,

Will this be possible? Will the computer boot from WWAN or from the DVD location? 

If OK - are there any prerequisites regarding the disk or its connections for it to work?

All useful help and tips are appreciated.