Instead, they have been included in the wider panel that thrashes out policy before the meeting with the local authorities and the Scottish Executive.
It had been widely assumed heads would be represented but the post-McCrone agreement left it up to the unions to decide. One of the principal reasons for removing the statutory powers of the old Scottish Joint Negotiating Committee (SJNC) was the dominance of the EIS. Now it has been re-created in the new Scottish Negotiating Committee for Teachers (SNCT).
The EIS has eight of 11 teacher members, with two for the Scottish Secondary Teachers' Association and one shared between the Professional Association of Teachers and the National Association of Schoolmasters Union of Women Teachers.
Kay Hall, salaries convener of the Association of Head Teachers in Scotland, which represents more than half of primary heads, described the panel representation as no more than a "sop". The heads' perspective was missing in the SJNC "and it is missing now", Mrs Hall said.
George Ross, secretary of the Headteachers' Association of Scotland, said:
"We are extremely disappointed the association has been denied a seat on the newly formed SNCT. The McCrone agreement embodied a new spirit of co-operation between the major players in Scottish education and this association has always entered into discussins in that spirit."
Mr Ross added: "It has always been the association's understanding that each teachers' organisation would have proper and public representation."
But Malcolm Maciver, the EIS's salaries convener, rejected the claims of the "derisory small" heads' associations. "We said what we wanted for ourselves but we are not the big bad people here," Mr Maciver said.
The EIS as the largest union demanded eight seats and left the others to decide on the remaining three seats. But heads say the carve-up was biased in favour of the EIS.
Primary heads met the Education Minister this week to complain about their omission but were told by Jack McConnell it was more important that they were involved in local talks rather than having a single seat at national level.
Mrs Hall believes that swift EIS action locally has tied down too many of the hours in teachers' new 35-hour week. The union, she said, was insisting on a set number of hours for parents' evenings, reporting and union meetings, and arguing for 20 per cent flexibility.
She accepts the 35-hour week helps control workload but said this should be done "by collegiate management, not by dictatorship". There would be little room for other activities for at least three years until continuing professional development requirements were fully introduced.
Mr Maciver said people would have to accept there would be 32 varieties of agreement. "There are bound to be bush fires but in most cases people are quite relaxed about it," he said.