Looking at the source of indicator-applet-0.3.7, it seems you cannot:
every installed module in some "INDICATOR_DIR" (it's
/usr/lib/indicators/3 on my 10.04 box) is loaded. The
"INDICATOR_DIR" is defined as a compile-time constant, so there is no
way to change it on a installed system. The relevant source is at
lines 703--728 in applet-main.c:
/* load 'em */
if (g_file_test(INDICATOR_DIR, (G_FILE_TEST_EXISTS | G_FILE_TEST_IS_DIR))) {
GDir * dir = g_dir_open(INDICATOR_DIR, 0, NULL);
const gchar * name;
while ((name = g_dir_read_name(dir)) != NULL) {
/* ... some lines omitted for brevity ... */
if (load_module(name, menubar)) {
indicators_loaded++;
}
}
g_dir_close (dir);
}
As a workaround, you could (warning: untested!):
compile your own version of indicator-applet, specifying a
different "INDICATOR_DIR": if you pass
--enable-localinstall to ./configure, then "INDICATOR_DIR"
will be located in $libdir/indicators/2 and you can also set
$libdir via command-line options to ./configure.
within your own INDICATOR_DIR, only activate the indicators you
want (just symlinking the system-wide ones should suffice)
use a ~/.gnomerc or ~/.xsession file to modify PATH so that
your own indicator-applet binary comes before the system-wide
one.