While SmarterMail has Routing Rules and Content Rules that overlap with Microsoft's rules system, there are some differences that are preventing us from integrating the two.
Before getting to the issues, it should be noted that routing rules don't really have any relevance to this topic. Routing rules are applied by SmarterMail's spool and serve as a way to define how a message should be handled to reach it's destination. Content filtering is the closest to Microsoft's rules since both apply to a message at the time of delivery.
The first issue is Microsoft's distinction between server-side and client-side rules. Based on our testing, the distinction is made based on the conditions and actions that are configured for the rule. From what I've been able to find, there is no documented list of which conditions and actions make a rule switch from being a server-side rule to being a client-side one.
This leads into another complication. Because one of the available actions is to stop processing additional rules, and because server-side and client-side rules can be mixed together, the server actually has to evaluate both server and client-side rules in order to determine which rules to apply. At the next sync, the server then tells the client which rules it needs to apply for a given message. In order to support that, SmarterMail would need to do the processing all at once, and then store information about the client-side rules that should be applied by the client.
Supporting Microsoft's rule system would also require a significant change to how Content Filters operate. Right now, when a message is being delivered, SmarterMail will only apply the first domain-level content filter that applies to the message and the first user-level content filter. Microsoft's rules, on the other hand, continue processing until there are no more rules or an action indicates rule processing should stop.
Another issue is that Outlook only allows creating rules with AND conditions while SmarterMail supports the ability to design a rule to use either AND or OR conditions. While not a problem for processing the rules, it would be an issue with syncing the rules and allowing users to fully manage their rules in Outlook.
All that is to say, while SmarterMail does currently store the binary data that defines the rules created by Outlook, integrating that rule processing into SmarterMail's current process would require a significant amount of work.