So I purchased a used roller D8 buggy and after installing the MMM and 2200Kv electronics, I went and hooked up my netbook to adjust some settings.

Updating the firmware was 1st and then went thru the settings....under the Advanced tab, there was no adjustable BEC found. I know it was there for my other MMM and when I hooked a new MMP as well.

Not sure on the generation of the ESC but I'm thinking it might be an older one.
Is this the reason for it not showing up? I emailed Castle a few days ago inquiring about this but they must be busy.

I have a HV servo coming for it so it looks like an external BEC would have to be purchased unless theres something else that someone can come up with.

At least as of a few years ago the MMM did not have an adjustable BEC. The MMP was the one that did.

Yes, as I said in my post, my other MMM has an adjustable BEC after software/firmware upgrades. This change happened almost a couple of years ago.