Timestamp is usually used for a temporary access to a stream (to allow an access to a stream for a restricted group of users). Timestamps usually expire so a stream URL is valid for a limited time.

And timestamps have nothing to do with start time and duration.

Every time I tried to save the .asx metafile I received the same value
<STARTTIME VALUE="7259"/>

The start time and duration will be different for other streams.

And you can't just get the URL of the mms stream here and record it. You should take start time and duration into the consideration.

To record such streams you have to use WM Recorder in the Pro or Ada mode
--or--
You can use a stream recorder like Replay A/V, Mass Downloader, NetTransport, HiDownload, WM Recorder (in the URL mode) that can postprocess .asx metafile and record the stream using start time and duration values.

I've tried all of these stream recorders and they gave me absolutely identical results that has nothing to do with the video I really wanna get. I even tried to enter start and end time in Net Transport, but I was unable to play the recorded video.

I've contacted the developers. Let's see how they can help.

What kind of problem with WM Recorder did you have? Does it record a different video? Or does it have a problem when recording?