Entering different quantities of the same product

[mauichiro]

Aloha,
I am new to Virtuemart and am not sure of the terminology I am looking for. I have 2 different sizes of vitamins to enter (90's & 180's).. I tried to enter them under the attributes but it is not working. I also tried to clone the product and change the variable. It works but i would prefer to have the customer choose the size needed in one product screen rather than have two product screens for the same product. I hope I am making sense here.  Any help would be appreciated )
Mahalo
Kat