Copy the XMIEXPRT.DLL file to Visio's DLL directory (i.e., C:\Program Files\Microsoft Office\Visio11\DLL)
Build the Visio XMI Export addon in Visual Studio (note: Visual Studio needs to be on the same machine as Visio. Even if you build the addon elsewhere, it still needs Visual Studio to work properly. No idea why. If you can get the addon to work without Visual Studio present, please comment on this page with details. Thanks!)
Start Visual Studio
File -> Open -> Project / Solution -> "$PATH_TO_XMIEXPRT/XMISample/VisioUmlAddon.sln"
Convert VisioUmlAddon? to new version if prompted by Visual Studio.
Under "Solution Explorer", open VisioUmlAddon?/Header Files/Vaddon.H. On line 100, change operator to int operator and save. (Not in Microsoft directions.)
Build the solution: on Visual Studio menu, choose Build -> Build Solution. Result is "$PATH_TO_XMIEXPRT/XMISample/Debug/VisioUmlAddon.vsl".
Copy VisioUmlAddon?.vsl to $PATH_TO_VISIO/1033/Solutions/VisioExtras.
Test the XMI Export addon in Visio:
Open Microsoft Visio 2003
Create a static structure diagram (sample attached to this page) and save.
On the Visio menu, choose Tools -> Addons -> Solutions -> Visio Extras ->
You may get an error along the lines of "Debug Assertion Failed! Program: f:\beta2\vctools\vc7libs\ship\atlmfc\include\afxwin1.inl line: 24". Press "Ignore", and enter a file name such as "StaticStructure.xmi" when prompted. An hourglass will appear, followed by "Export succeeded!"
Look at the XMI file
Open the XMI file - this file should open in any application that can deal with XML files, but you may want to open it with a text editor first just to convince yourself that the export facility actually generated an XMI file.
Download the zipped Poseidon installer from gentleware.com. (note: I'm using Windows XP, Poseidon SE 3.2.0). Unzip.
Run $PATH_TO_POSEIDON/bin/poseidon.bat
When prompted for a license, click "Evaluate" - this will open the gentleware website allowing you to request an evaluation key. Fill in the appropriate information and await your key by email.
When you receive the evaluation license, copy the license key and click "paste from clipboard" in the Poseidon license manager followed by "Add".
You can now click "Start Poseidon" on the license manager to launch Poseidon SE 3.2.0.
STC UML Diagram to OWL
STC is the Space Time Coordinate Metadata Specification for the VO - documentation and schema are available from the IVOA. A UML diagram of the schema was kindly provided by Arnold Rots.
Convert STC from UML to XMI
Open STC.vsd from Arnold Rots in Microsoft Visio 2003.
In the Model Explorer, open the STC drawing.
Export UML diagram to STC using the procedure described above - save as STC.xmi. The resulting XMI files contains elements relating to all drawings in the STC project, not just the STC drawing (note: I'm impressed! I thought this would be more difficult.)