Hi jfantasia,
Actually you don't need to perform any changes on the 6500 in order to resume the ip sla operation. Given your configuration, the keyword "forever" schedules the sla operation to run indefinitely.
After the connectivity is restored after a failure the Number of successes counter will keep increasing, if your 6500 keeps failing that would mean that your switch is still not able to reach it's ip sla destination.
6513#sh ip sla statistics
IPSLAs Latest Operation Statistics
IPSLA operation id: 1
Latest RTT: NoConnection/Busy/Timeout
Latest operation start time: 00:18:56 UTC Wed Sep 17 2014
Latest operation return code: Timeout
Number of successes: 82
Number of failures: 76
Operation time to live: Forever
6513#sh ip sla statistics
IPSLAs Latest Operation Statistics
IPSLA operation id: 1
Latest RTT: 61 milliseconds
Latest operation start time: 00:18:58 UTC Wed Sep 17 2014
Latest operation return code: Over threshold
Number of successes: 83
Number of failures: 76
Operation time to live: Forever
Hope this helps!