You dont really even need loopbe 30 - there is a free version that has only a single virtual connection, but that is all you need. Install Loopbe, and after restart it will show up as a midi output channel in Sonar. Make sure you select it as active under sonar>edit>preferences>midi>devices>outputs by selecting it's check box.
Next, open dmxis in standalaone mode from the windows start menu. The dmxis control desk will appear, and all of the banks/presets you have already created will be intact and can be found under the preset manager. Select file>preferences>audio/midi settings, then select the loopbe virtual midi cable as the active midi input by ticking it's checkbox.
In Sonar, you need to create 2 midi tracks to control DMXIS, both set to the Loopbe midi virtual output. One track (set to channel 15) will control DMXIS bank changes, so label it Bank. The other track (set to channel 16) will control dmxis scene changes and should be labelled Scene. Now the note c1 on the the bank track set to channel 15 will select bank 1 in dmxis, and the note c1 on the scene track set to chanell 16 will select scene 1 in dmxis. Bank and scene messages can be sent concurrently - there need not be any delay. Just move up through the scale to choose higher banks/scenes.
You can of course create multiple bank and scene tracks for more complex lighsthows. Their outputs are set exactky as described above.
Having DMXIS open in the background all of the time uses very few resources, and also speeds up the loading of songs as compared to inserting it as a vst device. The reason for this is that all banks/resets are loaded into memory for quick access. Run in standalone mode, this happens only once when you first open the program. Inserted as a vst, the presets are reloaded with every song, which can also cause issues with Sonars playlist and cause blackouts between songs.. The method of controlling DMXIS (Bank Ch 15/Scene Ch16) is the same regardless.
DMXIS is a great program and well worth taking the time to master. It works beautifully with sonar as well.