Yep, just install Lion onto that drive, and then choose it to be the boot drive from System Preferences > Startup Disk.
However, I think your'e going to be disappointed in the speed you're expecting. While FW800 has some decent data transfer rate, it's severely severely limiting the capabilities of your SSD's total speed.
What you should do is go to OWC and get the Data Doubler (
OWC Link, take out your SuperDrive and put your SSD in its place. Being directly connected via SATA will give you the full speed of your SSD vs the crippled speed of FW800.