How to call the plugin on Activate Quote button in ms crm 2011

Hi,

I want to update the string field when I click on the Quote Active button in MS CRM 2011.

I am calling the Plugin on SetStateDynamicEntity message Pre and Post stages but getting the error like as mentioned below.

In PreStage: The given key was not present in the dictionalry

In PostStage: The field is not update the form in readonly.

So how can I update the field on Quote Activate button click in plugin.

Please help.

Yadav

Yadav