A few things stand out as distinctive in terms of Ruby style. For example, for self.send "#{sym}=", val, I'd much prefer to see send :"#{sym}=", val. And "sym" is a poor choice of variable name semantically when it's really referring to an attribute name.

If I were writing this, I'd probably have a single hash that defines the SOAP names and internal names then dynamically create those accessors and dynamically create the hash in to_hash rather than have repetition. DRY and all that. So there are other ways to go about it.

There's not a great deal to go on, of course, but the chance of two independent Rubyists stumbling across an identical solution syntax-wise is far from high (though is not minuscule, either.)