You should be able to gather the product ID for the AIP-SSM from the output of the 'show version' command.  Note the called out entry below:

sensor# sh ver
Application Partition:

Cisco Intrusion Prevention System, Version 7.0(2)E4

Host:                                                        
    Realm Keys          key1.0                               
Signature Definition:                                        
    Signature Update    S490.0                   2010-05-12  
OS Version:             2.4.30-IDS-smp-bigphys               
Platform:               IPS-4240-K9

Serial Number:

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.

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Your Cisco account team or partner should be able to provide the correct contract type to provide signature update support.

Thanks,

Scott