If you can't distinguish the two and the genetics behave the same...then what is the difference?
To the OP:
Have you ever studied Punnett squares? If you have a basic understanding of how they work and the genetics you're dealing with (whether it's simple recessive, codom, etc), there are some good sites online that will calculate them out for you. Here's one I use sometimes (it allows you to name genes and add multiple alleles, which is nice)
http://www.silverfallchinchilla.com/...Calculator.asp