-snip-
In order to stake a new Bitcoin address, I think you have to sign a message with the former address which you've previously sent.
-snip-
You're absolutely correct. Here you go:
OLD ADDRESS
Out with the old; in with the new. -BTCforJoe 14MAY2017
-----BEGIN SIGNATURE-----
19STidiqGHqhuiEwmmgBeu4GCDJ8sxFrVE
H/qSVYBxpaGO2OCQBLz81Mjj7qkplvlg0OmTMy3OSyAdUIZBPLAhNgQ4N8VkwVqH1wQXsQizeuXmqjhAWX72Uwk=
-----END BITCOIN SIGNED MESSAGE-----
NEW ADDRESS
Staking BTCforJoe's Bitcoin address for bitcointalk.org - May 13, 2017.
-----BEGIN SIGNATURE-----
1JoeBTC3ZdeqxzBdXFS45R3Mnfi1DqMi1p
HA1ec0an1GmMc+PPF6XetPr7WRruVcrLp+QVps2FVP0MHA8OF7IZ0FMzyH2I9q7tLLuH5aH5RHg8YR9vv36XHgA=
-----END BITCOIN SIGNED MESSAGE-----