ISA Server Message Screener

If anyone is using Microsoft ISA I have just a couple questions on the Message Screener. I have that on its own server .37 running IIS5.0
Mail is on .2 and ISA is on on .25
1) Do Items filtered by the SMTP MEssage screener go to bad mail?

2) Secondly, If you have IIS 5.0 and Message screener on a server separate from Mail and ISA do you need to redirect SMTP mail from the ISA box to the SMTP Message screener box? If so how do I do that?

3) 3. Also is there anyway to check to see if the SMTP screener is actually screening any messages?

4. Is there a specific service that should be running on the IIS SMTP message screener server.