If you can't find an 1970 'A' fusebox you can use the 1971 'B'. That's what I did. There's two ways to approach using the 71 fusebox instead of the 70 one. One way is to just swap over the 8 and 9 connections with the 11 and 12.
This is a useful link.
http://www.thesamba.com/vw/forum/viewtopic.php?t=503832" onclick="window.open(this.href);return false;