Hi,
An associate of mine runs an ISP specializing in support for Large Multi-nationals, he had the same problem, ensuring that there were no holes in the sheilds, he ended up purchasing an automated patch monitoring/install app, and hasn,t had a problem since.
I tried to contact him for the product name, but he wasn,t in, I will send the the product name when I contact him later today.

It costs abt $2K.