after issuing "by force"cmd,Get confused about HADR

hi!

Imagine such a scenario:
1.My hadr primary server is down and unrecoverable.
2.I issue the "db2 takeover hadr on db sample by force" on the standby server. Now, the standby DB works correctly.
3.I stop the DB on the standby server.

here is the problem, when I try to start the DB again:

[db2inst1@host03 ~]$ db2start
01/20/2013 20:33:28 0 0 SQL1063N DB2START processing was successful.
SQL1063N DB2START processing was successful.
[db2inst1@host03 ~]$ db2 activate db sample
DB20000I The ACTIVATE DATABASE command completed successfully.
[db2inst1@host03 ~]$ db2 start hadr on db sample as primary
SQL1767N Start HADR cannot complete. Reason code = "2". START HADR AS PRIMARY cannot be issued on an HADR standby database.
[db2inst1@host03 ~]$ db2 start hadr on db sample as primary by force
SQL1767N Start HADR cannot complete. Reason code = "2".
[db2inst1@host03 ~]$ db2 takeover hadr on db sample by force
SQL1770N Takeover HADR cannot complete. Reason code = "5". Activate the standby database, then issue the takeover command.
[db2inst1@host03 ~]$ db2 activate db sample
DB20000I The ACTIVATE DATABASE command completed successfully.
[db2inst1@host03 ~]$ db2 takeover hadr on db sample by force
SQL1770N Takeover HADR cannot complete. Reason code = "5".


How can I get my DB back??

thanks in advance!