These facts are from K.m.ganguli translation of mahabharat
Reasons for the names of karna
1)Vasusena – This was his first name, it was because he was born with wealth (i.e earings and natural armour )
2)Radheya – because he is the adopted son of radha ,who nurtured him as her own son
3)Karna – The cutter or peeler of his own cover( Natural armour )
4)Vaikartana – because he had cut his natural armour and earings and gave it to indra
5)Vrisha – because he is ever truthful is speech,enagaged in penances, observant of vows , kind even to foes
By G.Gandherva
Karna The Great 