As said all above, there is no official vegeto character character in Earth Special Forces. Only model / skin replacements that will change the looks of ingame characters. But it won't add any kind of new attacks.
EVM however (Evolution Mod X) Yoink~.
EVM can be downloaded here: Yoink~
I'll thank you not to advertise EVM any further than need be. The link Grega supplied was plenty enough - Pain