In Maemo 4.0 Tutorial, section "Integrating Applications to maemo Framework" it is said:

It's not clear to me what four numbers should I use here for my own application installer. The MaemoPad example uses 0112 (and so does VNC Viewer which installation seems to be cloned from MaemoPad), so I assume it's ok to use this value, too?

But what happens if this value is already taken from another application, will this confuse the menu?

Is there an alternative method to create this symbolic link? (The hello-world-app example seems to use a different algorithm since it has no hello-world-app.links file in his debian directory inside the source tree!?)

I'm fairly certain that the only function this number has is to allow ordering the items in non-alphabetic order. That way the system doesn't need any special means to keep track of the order of the items. Instead, it can just list the files and sort them numerically.