how to customize outline mode

[Pete Siemsen]

I'd like to use Emacs outline mode to enhance browsing of Juniper
router config files.  I can't seem to set outline-regexp correctly.

Juniper config files follow a strict heirarchy - each section is
indented 4 spaces beneath its "heading".  Here's a fragment:

                group frgp2 {
                    peer 128.116.254.250 {
                        local-address 128.116.254.240;
                        active-source-limit {
                            maximum 100000;
                            threshold 90000;
                        }
                    }
                }

How can I set outline-regexp to make Emacs recognize 4 spaces as a
header delimiter?  I tried "(    )+", which didn't work.

-- 
-- Pete