How to spend bitcoins From Account and specify Fee
Please don't use bitcoin cores accounting system anymore (especially for new projects). It has been deprecated (and might be removed in near future).

A way of solving your issue would be by calling getaddressesbyaccount (get addresses of a specific account) and then use listunspent with these addresses.
Then you could create your own coin selection and use createrawtransaction singrawtransaction and sendrawtransaction.