hanibal,
How do you about what exactly happenend in the past?
There were reports that one of the Rigi brothers was arrested in Pakistan sometime back and that news went silent. Given that jihadi elements are operating in that broad area and our own sectarian tanzeems are partnered with the Taliban, it is possible that Jundullah people are in Baloch border areas. Have you forgotten that Iran almost declared war on us after Sipah-e-Sahaba goons went alongside Taliban and massacred Iranian diplomats in Mazar-e-Sharif. They were sent there by our brilliant GHQ as "dedicated fighters" without realizing their real sectarian goals.
We must make it clear to Tehran that public accusations will be met with strong counters, but remember that our government promised to work with Iran after the previous attack, but nothing happened.
We have to get real about the "tiger by the tail" problem as Jalaluddin notes above, because jihadi and Takfiri elements have no limits on what causes they support.
Yes, counter Iran's statement strongly but we must take action and take control of our land. Too many jihadi/Takfiri elements from all over the world are using us for their evil causes.
We are taking action, what else do you want, nuke the whole Pakistani population?
Iran if have some evidence of showing involvement of someone from Pakistan side the attack, then yes they need to share it with Pakistan, pointing fingers and playing blame games is not suitable, and like is said, it would not help Iran in any way.
On the different note, Why Iran is so frustrated? in their country, where freedom of speech and protest against "democratically elected govt" is taken as rebellion against govt? where every protest and bad doing is blamed on USA/UK earlier Iraq now Pakistan??