I want to create a new case from an opportunity.  I have built the connection between the two using a lookup relationship.  Now I have a button on the case related list to allow users to create a new case directly from the opportunity.  I want to make it as easy as possible by pulling in related information from the opportunity so the user does not have to reenter it. The challenge I now have is that I have multiple accounts with the same name and the user must then select the correct account.  Is there a way to pull the account from the opportunity without having the user look the correct one up from a list?  The button URL is listed below. 

/500/e?&cas4={!Opportunity.Account}&cas8=Medium&CF00N50000002Seac={!Opportunity.Name}&cas11="Opportunity"&RecordType=01250000000DvtV