Norwood's (and Central's) Ch9 partnership raises question

Article:
http://www.news.com.au/sport/afl/norwood-defends-partnership-deal-with-channel-9/story-fnii0294-1226886948353
Note this section of the article:
SANFL general manager of football Chris Davies said the agreement had not created any conflict with Channel 7.
“The SANFL does not need to sign off on the arrangement, it is an agreement between the television station and club,” he said.
This raises the question: Why couldn't North have Coopers as a sponsor?
http://www.news.com.au/sport/afl/norwood-defends-partnership-deal-with-channel-9/story-fnii0294-1226886948353
Note this section of the article:
SANFL general manager of football Chris Davies said the agreement had not created any conflict with Channel 7.
“The SANFL does not need to sign off on the arrangement, it is an agreement between the television station and club,” he said.
This raises the question: Why couldn't North have Coopers as a sponsor?