Connecting an REL sub to a Linn Classik

Could this be done well by terminating the REL cable with the Linn-style plugs on the amp side and plugging into the unused(speaker 2)terminals? I ask because the REL manual really stresses using the SAME terminals your speakers are connected to, but is this that critical? Short of connecting both the REL cable and speaker cables to common plugs, I can't think of another way to do it. Thanks.
To get the best performance out of the REL you should follow the REL instructions. They are very straightforward.
This question is vexing me as well.

I have a Linn Classik K (with the funny Euro plugs) and want to add a REL subwoofer (t-series) but the Linn plugs are not compatible with the REL wires: these plastic plugs will not allow sharing the Neutrik jacks.

OR I could disobey Rel's Prime Directive regarding amp connection and use PRE-AMP rca outputs and thus bypass the Neutrik speakon system that REL says is the magic of their subwoofer system (the way the subwoofer disappears into the music)..

Is there another way? Perhaps a different subwoofer of similar quality (under between $400-1000). I've been thinking of REL because they are reputed to match nicely with sonic signature of my main speakers, Vienna Acoustics Mozart Grand.

This is for music only, not video. Acoustic jazz; classic soul; alternative hip hop.

Thanks, anyone.
Use the unused speaker terminals...the REL presents 100,000 ohms or something to the amp so you can run it as an "extra" speaker and it will get the same signal as the main speakers (since it's the same amp...sort of the point) simply from another output, and not bother the amp. Also, I don't see any reason why you can't run a REL by taking a signal from the speaker terminals the amp is already driving (may seem weird weird but makes sense...take one plus side from each already hooked up speaker and a negative from one and yer in business, albeit with strange wiring) as it results in the same thing. Also, Neutrik plugs are really easy to wire up for RELs and the proper hook-up is on the REL site.
Thanks for your thoughtful advice. The problem with the Neutrik speakon and Linn Classik K is that the speaker terminals on Classik are not exposed but totally encased in plastic rods: you have to use special Linn connectors on your speaker cables. So there's nothing to wrap around, in the Neutrik fashion.

SO, the Neutrik thingies have nothing to grab onto, unfortunately. I should have thought of these little things when I bought this otherwise sweet-sounding amp.

So, yes I'll probably have to go with the empty speaker terminals.