Does it have to be a floppy? This is kinda hard these days, as the default kernel and initrd exceeds the default 1.44 MB available on a disk..
Other ways to achieve this way of working:
- Network boot, does your system support PXE Network Booting? You should alter the configuration of the dhcp server and set up a TFTP server which provides the network boot options
- USB stick booting, does your system support booting off a USB stick? This allows bigger kernels and initrd images to be used. This prevents the need to have an (altered) DHCP server and a TFTP server.
On both options, the boot method provides a first step to installing.. on both ways, you'd have to provide a Network access to the install medium (DVD), either through NFS, HTTP or FTP.
If there ARE ways of using a boot floppy which will have you continue booting off some network method, I am not aware of this, sorry (as I stopped using either floppies or physical media since a couple of years now).
Hope this helps... or if not, let me (us?) know..