Good post about MSF 4.0 by Charles Young
When testing policies that use a lot of database facts in Rule Composer (or .NET components that access database) you may not want to hardcode connection strings into BRE as constants. There's a better place to keep them - the BRC config file. Since there's no such file we can make one. Go to the Biztalk installation folder and create file named Microsoft.RuleComposer.exe.... Simply put in any configuration settings you want as in regular .net config file, for example: <configuration> <connectionStrings>...
Richard Seroter shows here some magic to enable static methods invocation in Business Rules Engine without passing fact instance. Really handy