Bad Request "The Access Manager WebSEAL server recieved an invalid HTTP request"

In most cases, this can be resolved by modifying the following (default) declaration in the webseald conf file:
max-webseal-header-size = 0

to a fixed value, such as:

max-webseal-header-size = 3192

This will cause webseal to split the header (packet) at the given value if the header size is above the given value. Backend server processes meeting the HTTP 1.1 spec will reconstruct the header if applicable.