I just remember, some years ago we made a repair of these on my wrenching buddy's E32 Alpina B12 with M70 engine and we disassembled the valves to study the design and we found another possible part number and installed it.
Pics Bosch 0 280 142 150 + BMW 13901726705 made by AB-Elektronik, used from 11/1989 in E30, E36, E34, E32, Z1, Z3, Price abt. EURO 70. Also fits on E32 750, tested on Alpina B12 M70, pics below, ETK only mentions M30:
comparison of both valves from outside http://2.bp.blogspot.com/-mZZ3yrbTUo...0/P1140101.jpg
comparison connectors http://4.bp.blogspot.com/-HixJ6Wp070...0/P1140102.jpg
http://4.bp.blogspot.com/--Xa7pKon4M...0/P1140104.jpg
the plastic Y-piece usually breakes between valves and charcoal cannister http://2.bp.blogspot.com/-3yf8sOJPuW...0/P1160664.jpg
steel replacement of Y-piece http://4.bp.blogspot.com/-LM3DVJLycM...0/P1160692.jpg
disassembled valve
http://4.bp.blogspot.com/-ZF4luzt4cs...0/P1140107.jpg
http://3.bp.blogspot.com/-PS8Kbg5Hny...0/P1140112.jpg
http://1.bp.blogspot.com/-Q7AYHSDmzn...0/P1140113.jpg
http://3.bp.blogspot.com/-4ZNHsDbeOW...0/P1140115.jpg
http://2.bp.blogspot.com/-JeF3EO9PUX...0/P1140116.jpg
http://3.bp.blogspot.com/-S2HgbwNYa3...1600/valve.gif