There's one easy method, but as Remington found out, it isn't strong enough for serious bayonet work.
The early magazine extension was part of a military program, and the end of the extension had an extended cap that fits the mounting ring on a bayonet. (For some reason Remington never saw fit to change it, and current extensions still have it).
The mounting latch was attached to the bottom of the Remington barrel clamp.
The extension has a groove in the tube, through which the barrel clamp mounting screw passes.
This serves to prevent the clamp from moving forward under recoil OR when using the bayonet.
The groove also served to position the clamp in the right spot for the latch to engage the bayonet lock.
Here's what I did on request years ago.
I either made up a new latch lug, or cut one off a damaged M14 rifle flash hider and welded the latch to the bottom of the Remington barrel clamp.
This works, but as Remington found out, if you really use the bayonet with any force, the clamp just isn't strong enough to stand up.
The only way that really works is either an old style barrel shroud as used on the old military Winchester '97, or a Marine Corp type long clamp device that wraps around the barrel and the extension and offers enough reinforcement to take the stress.
Probably, the easiest method that will stand up, is to buy a steel barrel shroud and weld a reinforced section on the bottom with a latch lug on that.
The new shrouds have a clamp-like end that tightens around the barrel. These may interfere with an extension, so a new, longer front section would need to be added to wrap around the extension.