Trouble finding extension for Multiple SKU#s opencart 1.5

For our online store, one of the products we sell is tech shirts,

we recently purchased an options boost for opencart 1.5 in order to get the ability to put in options when purchasing such as choosing a color

that option works great except for the fact we would also like to have customers be able to choose both color AND size
each of our shirts has a different sku number and we would need to have the ability to put in the different sku numbers for each option...

does anybody know how to resolve this with maybe another extension or something??
thanks!!

Create option combinations for values

Instead of 2 options

Color:
- Blue
- Red
- Black
Size:
- S
- M
- L

Create one combined option:

Color/Size:
- Blue/S
- Blue/M
- Blue/L
- Red/S
- Red/M
- Red/L
- Black/S
- Black/M
- Black/L

oh!! great idea! thank you so much, will do that now!