automatically callout the P/n of instance

Hi everybody,

I'm exploding an assembly to illustrate the components. I would like to know if there is any method in PMI that I can use to automatically call out the name/part number of the instance in the assembly. I visualize this is how it should work:

I pick an instance n the asssembly
It should automatically key-in the part number of the part.

I'm very new to UG and I use ideas. So bear with me if I'm too greedy. I know there are some special symbols like <@partname>, but it does not work for me

thanks in advance
Vic