add jobs to queue in background

[ras-eric]

hello, is it possible to add a job to the queue that is running in
background from a new lftp session?
i have written a small script that uses the command "queue mirror $dir
slot:2" to queue up fxp transfers.. but it doesnt work as expected:
when a second job is added (same site) it will not wait untill the
first job is complete but start immediately.
greetings, ras-eric