Open Outlook Express. From the Tools menu, click Message Rules, and then click Mail. You are presented with the Message Rules dialog.

Click the New button. You are presented with a dialog titled New Mail Rule.

You are first asked to select the Conditions for your rule. Select "Where
the message body contains specific words"

Then you are asked to select Actions for your rule. Select "Move it to the
specified folder"

Next you are asked to edit the Rule Description. First click the underlined
text that says "contains specific words". It will ask for a specific word
or phrase. Enter EXACTLY the following (without quotes): "This mail is
probably spam. The original message has been attached". Click OK.

Next, click on the underlined word "specified". Select a folder you would
like to move the messages to, or create a new folder. Click OK.

Now click OK to save your new mail rule and OK agian to exit the Message
Rules dialog.

Note: It is recommended you periodically review the messages in case Spam Assassin generates a false positive and flags a message as SPAM that is not SPAM.