That having been said, here are some rules. They're mostly AToW in nature, but here you are:
In Total Warfare, Battle Armor units do not have any cargo carrying capability, beyond what they can carry internally as Mission Equipment.
For ATOW, their cargo carrying capacity is based on the STR of the user, plus any bonuses provided by the suit, plus a bonus based on the type of suit:
PA(L) = +1 STR
Light = +2 STR
Medium = +4 STR
Heavy = +6 STR
Assault = +8 STR
That will be errata'd in to p. 169 of ATOW, under encumbrance.
So, an STR 10 guy in an assault suit would math to STR18 for encumbrance purposes, so at 270kg, the encumbered penalty starts kicking in.
A Myomer Booster adds +4 STR.
In combat, it's a +0M/12 advantage.