I am not able to record MIDI drum tracks in Sonar X3 from my Alesis SR18.  I have the MIDI clock set to SLAVE in the SR18 and have the Sonar set to send a MIDI clock.  When I click the RECORD button on Sonar X3 it does indeed play the SR18 however, no MIDI events are recorded into Sonar.
 
I am using a UM-ONE MIDI to USB cable from the SR18 to the computer.  And believe it is configured correctly as it does start the SR18 when I click the RECORD button in Sonar. 
 
I have checked the drum tutorials and must admit this is all rather confusing. 
 
Any help getting this to work is much appreciated.
 
Thanks

I have run into issues  like this years ago and it is usually something very simple once it is isolated.  Sometimes it is just a matter of goimg through menus on drum machine. Check things like whether  the sr18 is sending midi info like  note  and velocity and that the midi track is armed and set to record on proper channel in Sonar. Also ch3ck in preferences to make sure sr18 is a listed input device. Do you have a midi track created to record to and is that midi track set to recieve info with sr18 as source. Bottomline is regardless of device, it is tyoically just a matter of crossing t's and dotting eyes on midi i/o path.

also, keep your head up. It gets easier :)

I have done same thing with my SR16 several times with good results. I suppose you want to copy your midi groves from SR18 to Sonar. The culprit is your midi interface. Try these simple steps and see what happens.
1. Connect SR18 midi out with your interface midi in.
2. Insert a drum track for example Session Drummer 3, choose drum kit, check if you hear sound by clicking on any drum
3. Press play on SR18, you should be hearing SR18 groove played on SD3 ...
4. ... and be able to record it as a midi.

IIRC you need to set MIDI to transmit from the device. It's something like "DRUM OUT" in the settings (of the SR-18). It needs to be set to "On".
 
HTH.

Ok... I think I have it.  The issue was turning on the DRUM OUT as you mention Karl.  Thanks.  I also had to turn on the PERC OUT as well.
 
I was able to create 4 different .mid files from the SR18 A/B/FILL patterns.
Now all I need to learn how to do is edit the recorded tracks easier. :)

I have my old Roland 505 always connected to my system and find it handy for quick and easy pattern playback. 
Even though I dumped all it's patterns into Sonar a long time ago like you are doing, I still will fire it up for both me and clients when I don't have time to muck about looking for the best pattern to fit a new song. Way quicker to dial through the pre sets as you play along. 
It set so I can record either the midi or the audio at any time. Sonar controls the clock that's all. 
I also use it stand alone to find song tempos quickly as the dial is much easier to adjust than Sonars tempo number system.