Cost Assignments and PSI

Hi again,
After some days trying to work arround to create cost assignments through PSI without luck I found this post: http://projectserverblogs.com/?p=1540
If you look this post you will find the next lines:
Further compounding this concern is item three under User scenarios to avoid, which states that tasks with Cost Resources assigned to them should not have any assignments (meaning assignments to Cost, Material, or Work Resources) updated on that task through PWA or the PSI. This means that if you choose to disregard item one in Best practice use cases, you may only perform task updates from within Project Professional. However, it is possible to configure the system so that it will only accept Task Updates through PWA. This essentially eliminates Cost Resources as a tool for organizations who’ve chosen this configuration.
As soon as I have read this lines I started to find a work arround to create and modify cost assignments through PSI.
We couldn't find any solution yet, but in out project we use Reporting Services to make our reports and only PSI to modify tasks from Projects so we can create a new table assignments in Reporting database wich has the same structuree than MSP_ASSIGNMENTS.
Now our client can modify It's cost assignments of his tasks and get his reports through Reporting Services. Of course, if you open your project with Project Professional or use costs views you will not be able to see anything.
So we still wait for a solution for this problem wich seems that only Microsoft can solve.