In general everything brings down to figure out:
-ID
-Position
-Possible value range

There seems to be two possible ways to figure that out.
1) Use USB sniffer together with X-Edit
   Once you set up X-Edit and usb sniffer, set some option.
   USB sniffer should report something like this being sent to device:
   (all numbers here are hex)
   04 F0 00 00 04 10 00 5E 04 02 41 00 04 30 09 00 07 00 34 F7

   To get SysEx command out of it, remove every 4th byte, so we have:
      F0 00 00    10 00 5E    02 41 00    30 09 00    00 34 F7

   SysEx message format seems to be formed like this:
   magic bytes - F0 00 00 10 00 5E 02 41
   status byte - in this example 00
   ID - in this example 30 09
   Position - in this example 00
   Value - in this example 00 (can be more bytes long, see below)
   Checksum - to calculate it, XOR all bytes, and then XOR it with 07
   Every message ends with F7

   Status byte bits explained:
      7th - ???
      6th - if active add 80 to ID
      5th - ???
      4th - is active when value will start with length
            In such case value can be something like:
              01 12 or 02 12 34 or 03 12 34 56
            and proper values are:
              01 - 12
              02 - 1234
              03 - 123456
      3rd - when 4th bit is also active, and first value byte is 01
            then add 80 to value
      2nd - when 4th bit is also active, and first value byte is 02
            then add 80 to value
      1st - when 4th bit is also active, and first value byte is 03
            then add 80 to value

   So for above example:
   ID = 3009 (hex) = 12297 (decimal)
   Position = 0
   One of possible values is 0. Usually value range is 0 to 99,
   albeit in some cases it's different - you have to check what values can
   X-Edit assign (there doesn't seem to be any sanity check in firmware)
   This is especially needed for IDs that set some effect type.
      
2) Save preset patch
   Patches seem to be simple XML files.
   Every parameter is written like this:
     <Param>
       <ID>65</ID>
       <Position>2</Position>
       <Value>0</Value>
       <Name>Pickup Enable</Name>
       <Text>Off</Text>
     </Param>
   ID is ID, Position is Position and Value is one of possible values.
   To get all possible values you can:
     do
       change value to next one possible in X-Edit
         (for example next effect type)
       save new patch
       check patch file and note the change
     while you don't have all possible values