I know it's not easy timetabling and choosing teachers for new courses.
You can consider various options. You can have an experienced teacher take this class. I don't think IT English (or any other form of technical / business English) exists as a separate language. General English structures are being used with technical vocabulary. Very often students who study or work in the field know the technical vocab but don't know how to use structures correctly. An experienced teacher should know how to combine the two. In fact, the teacher can exploit the situation by asking students to explain aspects of their work.
If possible, the teacher who previously worked in IT could take the classes for a few sessions. This will give the students an opportunity to use the language with somebody who understands their subject. If this isn't possible can he/she provide some input for the planning of the lessons? I think the two together could make a good team.