I think this is not possible using the existing functions, due to the way scheme gets called. The function run-scheme
contains an explicit call to the function split-string-and-unquote
on the scheme program name. As a consequence, the path to the scheme program will always be split at the first space. This means it is impossible to use a path with a space in it.
This is a bug that should be reported to the maintainers I think.