If a vendor like Microsoft isnt listening, its probably because you havent got their attention. There are a number of ways to do that, but the easiest and least likely to be taken as a personal attack is simply to be candid and tell the vendor what you need them to know as often, and as consistently, as you can.
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Also, it helps to have milestones and meeting minutes, vendors get distracted (and few IT shops have either milestones or meeting minutes). Those that do will probably be more effective at having their needs addressed more quickly.
Fault and Project Ownership: EMC
One of the big problems with Microsoft is they generally dont supply the solution that relates to their technology. They may provide a lot of it, but someone else often has to finish the work so that it meets requirements. This is true of big products, and small systems (for instance the most interesting phone based on Microsoft technology is the Neonode, a phone where the phone maker did its own interface on top of CE and created what could be a legitimate iPhone killer).
For large implementations we regularly use third party services organizations, VARs, or specialists to complete our projects. And many of these folks, when they run into a problem, point at Microsoft as the cause regardless of what that cause might be.
A few years back I took a look at a Linux desktop implementation which resulted from what was presented as a Microsoft screw up. It turned out that it was the service provider that screwed up and then used the event to raise their monthly fee for support for the now Linux environment substantially. It is probably a wise practice to talk to all of the parties involved when there is a screw up and make your own determination with regard to who owns the blame and what the fix actually should be.
The reason I called EMC out at the head of this section is that the company has decided to go down the non-traditional path of taking ownership for the joint Microsoft projects they take on. They are developing a reputation for taking responsibility for related problems regardless of who is at fault and focusing on getting those problems fixed rather wasting time blaming Microsoft.
Id like to see more solutions providers go down this path as, like you, I dont really care who is at fault, Im much more interested in getting the problems fixed then hearing excuses regardless of what the excuse actually is.