Sales Manager 2.5.7 is the version that will come with SMP 3.0 files and instruction to install. Older Sales Manager 2.5.X (2.5.4) only was released with SMP 2.3 with the expectation that the customer will manually fix it or migrate to SMP 3.0. This is not a trivial step as it may require you to get access to the source code and you may need to sign some papers that you are going to void support if you do so. Wait til 2.5.7 so all the QA and test is already done for you with proper instructions on install. The old SAP note that claims that the earlier Sales Manager 2.5.X versions supports SMP 3.0 will be fixed.
Best Regards,
Mark Pe
SAP Senior Support Engineer