GC: need help with dr.montague and enemy parts

[Ae0n]

i'm on gamecube and i have a problem with turning enemy item parts into weapons.
i have done all which is said in the guide about enemy parts but dr. montague doesnt offer me to make a weapon out of my booma's right arm. he just talks in the Dr Oslo's research mission about that robot girl (forgot the name) and thats it.
and i did not have the item in the bank.
so what should i do?

[bordering]

go back and read the guide again. i'm pretty sure that you have to complete the quest "doc's secret plan" in order to be able to turn parts into weps. when you've finished that mission, you need to load up another in which he appears (i usually go to "unsealed door") and he'll change it for you there.