How do I use the new LONG variables?
Just as you did - nice job!

LY = 1234 * 4321 = 5332114 = $515C92
The lower word of the long is $5C92 = 23698

It looks like the # preceding variables in the DEBUG command is only set up to handle words (or bytes) and not the new long. I do not have 2.50 as of yet so i cannot see it "they" updated the manual in the debug section to note this.