You can use the static variable QUOTE or chr(34). Never the less, I think I saw an Erel's post these days, where is said that we can insert the " inside a string, but I cannot remember right now the link :sign0013:
This is true. In general, I've seen some inconsistencies moving from " to ', I think it was in javaScript, but can't remember now exactly. Anyway, nothing to do with b4a (actually seen it in php's echo).