Monster Hunter Freedom Unite: Getting Vespoid spoils and fighting Tigrex

After starting a new game due to mad explosions on my PSP, I now am in need of some help. I wish to carve some Vespoids, but whenever I beat them they always smash into many pieces, giving me no opportunity to carve at all. I somehow did it once, I got the Vespoid to the ground without it dissapearing. I'm using all the starting equips. So does anyone know a specific weapon or specific attack I need to use to get them so I can carve them? Also, another matter. Tigrex. I read one guy's strategy, but He just hits too hard if he actually gets me. Usually 1-2 hits and I'm dead. I can't make all the powerful equips yet because I don't have access to those materials. The Tigrex I'm talking about is from the "Sinking feeling" Elder quest, HR1. Am I actually supposed to fight him or just do what the quests ask, which incidently, has nothing to do with fighting Tigrex at all.
Post Merge: [time]1277282589[/time]
Anyone~?

for the vespoids you have to use poison bombs to kill them with out destroying them. as for the mission you are just supposed to do what the quest says because he is to strong to beat.