The HpWeapon01 etc Hardpoints themselves will not show in the game, this is normal. The reason the standard models show a “mounting point” is because it is a shape put on the ship model.
If this is what you mean, then you need to copy the shape by importing the model .cmp file into MilkShape, copy it from another hardpoint location, and put it where you want it, then re-export the cmp. This is tricky if you have not done it before.
Or if you mean you can’t use the new hardpoint then:- Can you mount guns or equipment on them in the game (depending on what types you defined them as, in shiparch.ini), for example:
…
hp_type = hp_gun_special_1, HpWeapon01, HpWeapon02
hp_type = hp_fighter_shield_special_4, HpShield01
hp_type = hp_fighter_shield_special_3, HpShield01
hp_type = hp_fighter_shield_special_2, HpShield01
hp_type = hp_fighter_shield_special_1, HpShield01
hp_type = hp_thruster, HpThruster01
hp_type = hp_mine_dropper, HpMine01
hp_type = hp_countermeasure_dropper, HpCM01
hp_type = hp_torpedo_special_2, HpTorpedo01
hp_type = hp_torpedo_special_1, HpTorpedo01
…