pagination segment lost

[eluser]zenon[/eluser]
I've noticed another problem still using uri :

Supposing my URI is

http://localhost/myapp/index.php/places/...page//id/1

when i call

Code:

$this->uri->uri_to_assoc(4);

a print_r of the given array produces

Array ( [page] => id [1] => )

but it's not my expected result, because page should be false and id = 1.

What can I do to handle all those params value that can be valorized or not according to the situation?
Anyway I would not to use number segment.