Transferring scouts is done using the Transfer tool, separately from the recharter (I think). There’s a recent how-to posted here: How can my unit transfer Scouts to troops?
ETA: Note that the instructions are for the outgoing unit side (e.g. pack) rather than the receiving unit (i.e. troop in your case).
ETA2: I think the receiving unit has to have online applications enabled, but maybe @DonovanMcNeil (the document’s author) can clarify that.
