How do teachers view Special Needs Assistants (SNAs)?

There seems to have been very little thought put into the implications for teachers of introducing special needs assistants into schools in Ireland.  This is unfair to both teachers and to those who take up posts as special needs assistants. While some teachers see the SNA as an asset in the classroom, the majority do not seem to know how to treat this intruder into their classroom and some are positively hostile seeing them as an unwanted intrusion in their terrritory.