Heya,
I spent some time testing this yesterday, in fact. Since the ASM acts as a full proxy, the connections are never opened to the pool members. Watching Slowloris traffic on the wire showed that it consumed threads by sending a POST with a Content-Length that it never fulfilled. Since ASM doesn't open a connection to the servers until it has received, parsed, and approved (based on the security policy), and Slowloris never completes its request the ASM never opens a connection to the servers. Since the point of Slowloris is to not simply DoS by volume (the default number of sockets is only 500), this should probably not cause any problems.
// Ben