It has been a surprise to most (me included) but within the PCI requirements it specifies that you must disable any IPS functionality you have for the scan vendor. The idea is that an IPS should only used to mitigate issues until they can be solved....
I'm assuming you mean Tripwire Enterprise.Tripwire supports an "agent-less" node. This is how they handle most network devices I believe. The TE (frontend) server has an agent installed on it and it initiates the connections and sends commands. Tr...