Share login session

[nfinity]

Hello.

I have own my site. I try to use VB5 as my forum. So I need to use my login session with VB5. How can I share my site session with VB5. (And this is my first time to use VB software.)
The other question is;
If I change some on login page, do I need to reset cache?

vBulletin 5.0.0 Beta 18
PHP Version 5.3.3/Apache/2.2.15 (CentOS)/Zend Engine v2.3.0/Mysql 5.1.61
Linux PortalQA 2.6.32-279.5.2.el6.x86_64 #1 SMP Fri Aug 24 01:07:11 UTC 2012 x86_64

session

Session Support enabled
Registered save handlers files user
Registered serializer handlers php php_binary wddx

Directive Local Value Master Value
session.auto_start Off Off
session.bug_compat_42 Off Off
session.bug_compat_warn Off Off
session.cache_expire 180 180
session.cache_limiter nocache nocache
session.cookie_domain no value no value
session.cookie_httponly Off Off
session.cookie_lifetime 0 0
session.cookie_path / /
session.cookie_secure Off Off
session.entropy_file no value no value
session.entropy_length 0 0
session.gc_divisor 1000 1000
session.gc_maxlifetime 1440 1440
session.gc_probability 1 1
session.hash_bits_per_character 5 5
session.hash_function 0 0
session.name PHPSESSID PHPSESSID
session.referer_check no value no value
session.save_handler files files
session.save_path /var/lib/php/session /var/lib/php/session
session.serialize_handler php php
session.use_cookies On On
session.use_only_cookies On On
session.use_trans_sid 0 0

[Zachery]

vBulletin doesn't use php sessions. You need to write custom code to validate the user data in some way.