Nope, you must remove the front case to get the rear shaft out. No way around it because you need to replace or modify the part of the shaft that stays in the oil pump.
BTW, the mitsu part numbers for the b-shaft removal are:
Front cover cap MD092785 $5.95
Oil pump stub shaft MD098626 $7.61
b-shaft bearing MD103722 $8.02
b-shaft bearing MD040597 $9.26
You wont need the bearings if you can remove the old ones and flip em without mangling them.
The reason for leaving the front shaft in is cuz its a major beeotch to remove with the engine in the car. It can be done if you hack saw thru it once or twice. But even if you do get it out, fliping the bearings would be a nightmare.