Possible to re-enable IPv6 without rebooting?-Collection of common programming errors

I have a machine running CentOS 5.8. IPv6 was disabled by creating a file /etc/modprobe.d/disable-ipv6 with the following contents:

options ipv6 disable=1

Removing the file and rebooting the machine should re-enable IPv6. Is there a way to enable IPv6 without having to reboot?

Additional info:

I found something that said to echo 0 > /proc/sys/net/ipv6/conf/interface/disable_ipv6, but /proc/sys/net/ipv6 does not exist on this machine.

sysctl shows nothing about IPv6:

# sysctl -a | grep -i ipv6 | wc -l
0

The ipv6 kernel module is loaded:

#lsmod | grep ipv6
ipv6                  437857  1 cnic

Attempting to remove it throws an error:

# modprobe -vnr ipv6
FATAL: Module ipv6 is in use.

# modprobe --show-depends ipv6
insmod /lib/modules/2.6.18-308.13.1.el5/kernel/crypto/crypto_api.ko 
insmod /lib/modules/2.6.18-308.13.1.el5/kernel/net/xfrm/xfrm_nalgo.ko 
insmod /lib/modules/2.6.18-308.13.1.el5/kernel/net/ipv6/ipv6.ko

Modprobe says crypto_api depends on the ipv6 module. Unloading and loading that on a running webserver does not sound like best idea.

I tried rmmod as suggested by @Zoredache:

# rmmod -v ipv6
ERROR: Module ipv6 is in use by cnic