Copy the ipsec.lrp or ipsec509.lrp package to the floppy. Also, you must copy the mawk.lrp package since it is needed by the ipsec scripts. You do not need the ifconfig.lrp package
You may need some space to store the packages and the ipsec module and generally a single floppy won't be enough. Check the Bering user's guide section about "Booting Bering from different boot-media" for tips.
Modify the syslinux.cfg file to load the new packages. It might look like this:
display syslinux.dpy
timeout 0
default linux initrd=initrd.lrp init=/linuxrc rw root=/dev/ram0 boot=/dev/fd0u1680:msdos
PKGPATH=/dev/fd0u1680 LRP=root,etc,local,modules,iptables,pump,keyboard,shorwall,ulogd,dnscache,weblet,ipsec,mawk
The last two lines ("default linux ... ipsec,mawk") must
be typed as a single one in syslinux.cfg
Copy the ipsec.o module from the modules package which matches your kernel. Don't even try to do this with mismatching modules, kernel or ipsec utilities!
Install this module using the method described in the main Bering documentation.