Dear Forum Users,
when recording the TD-9 Drum Set over Midi with our ESI 1010 PCIxpress soundcard, we have the following problem:
Hard hits are not recognized by Sonar X2 or the soundcard. Not all Midi data is recorded depending on ist velocity level. We recorded drum hits at increasing strenghts. While the audio output of the TD-9 is about  at half of its maximum velocity level and above, Sonar X2 does not show any Midi Event anymore. Hits below this velocity value are recorded well.
We tried the same on a RME Fireface 800 soundcard and Sonar Platinum - everything works fine.
 
Thanks in advance!
 
Best regards,
Tom

That's all very old technology as far as I can tell by looking it up. 
X2 was a buggy version of Sonar and not supported but that said I doubt if that's your problem. Sonar has never had an issue with recording midi and velocity matters not,, just another 1 or 0.
It's most likely the interface, Are there drivers for the 1010 for the version of windows your using?  You almost answered your own question by stating it works fine when you use an RME.  

If SONAR works with the RME and not the ESI, the fault is likely with the interface hardware or driver. Inspect the MIDI data before it hits SONAR with MIDI-OX or similar utility to confirm data is arriving as expected from the interface.