Hey mate,
Two ways you can go from here:
1) Manually tell Cubase which patch you want it to recall (using MIDI program changes), however, this won't reveal the patch name itself in Cubase.
2) Create and/or edit the patch name document Cubase uses to display patches (which also uses the same MIDI program change commands embedded in the file).
Let's go with the first, simplest option to get you up and running...
1) Call up the patch you want using the XL-1's front panel.
2) Press the "Audition" panel on the XL-1's front panel.
3) Note the MSB and LSB values displayed on the LCD. These are the program change commands that correspond with that particular patch. The MSB relates to the ROM and the LSB relates to the bank. Get this wrong in Cubase, and you'll get the 'not installed' on the XL-1 display. In your example, there's simply no "bank 4" for the particular ROM it's attempting to access.
4) MSB/LSB eh, well what's that all about, you ask?! Well aside from standing for Most/Least Significant Bit, these are continuous controllers (cc##), not unlike the controller used for Filter Cutoff (cc74) or Filter Resonance (cc71). Now I'm not sure how Cubase labels things (Jester? Anyone?), however, in Pro Tools, in the program/patch change/select window, rather than displaying fields labelled MSB and LSB, it shows fields marked cc00 and cc32. All you need to know is MSB = cc00 and LSB = cc32.
5) Still with me?
6) So putting it altogether, take the MSB/LSB values from the XL-1's front panel after you hit "audition" for the current patch, and copy them into the cc00 and cc32 (if they're not already labelled as MSB/LSB) in Cubase's patch select window.
7) Sorted! Looking back at that waffle, I could have probably skipped steps 1 thru 5 and you'd still have got it. :-[
Let me know if that gets you started, and we can tackle your patch name files later down the track. And looking foward to a review on the Beat Garden. :cans: