Can't get junk folder in one account

I have seen this question before, but I don't recall an aswer, even if it was mine. Well, someone found one of my e-mail accounts, and there was a Junk message, which had slipped by the ISP spam controls. I had all my settings, except that the folder to which I should have sent the message was blank, I selected the correct account, closed, and when I went back, the line was blank.
I remember, long ago in an early Netscape7.x that I had a similar problem, and I had removed the account, and then put it back in, which is a bother.
If that is the only spam, I can handle things manually, but any idea is welcome.
This was in TB1.5.0.2.

 

Westside,

To clarify, you marked the message as Junk, or do you have a Message Filter indicating a folder for Spam?

 

I could not mark it as Junk, and there was no way to send it to the Junk folder.
This has nothing to do with a Filter, which are sent to Trash.
I received a message from someone, I did not know, so I proceeded to view it without opening it. Next, I forwarded it to my ISP abuse. and, finally deleted it.
But still no Junk folder in sight.
By the way TB1.0.7, which I still have has a Junk folder, and the message was easily put there. The difference was than in 1.0.7 I have a specific Junk folder, while 1.5.0.2 just a blank.