This thread in the OpenMaps forum came up in my search today. The problem posed is similar to mine, though I see from the response that it might be more effective to create a new thread on the topic and that I should be as precise as possible. I wanted to document this for others. The main reason I feel like this discussion belongs better in the Visualization forum than the Microstation forum because if others are anything like me, it'll feel more like a Microstation problem than anything else.
(Yes, I'm a little behind the times still using V8i.)
First of all, I'm working in a survey plane that is not coincident with the state plane. (I don't understand what the benefit might be here, but basically our client wants us to be working in a plane that is translated by some number of feet.) This makes dealing with other teams frustrating. Also, when I export my linework to KMZ, I'm seeing a difference in the ballpark of 100 feet from what I expect.
The thread linked above mentioned the PRJ file from their GIS work. I have a PRJ file that appears to have the information that I need to save to Microstation's GCS interface, but I couldn't make sense of how to copy any projection and edit it as I needed to.
The response in the thread mentioned DTY files which made no sense to me. So here I go, in an attempt to tie it all together.
First, you need to have access to Map. See that you do have access by looking for Applications > Maps > Activate Map. I don't know anything about licensing this module and what it takes to have access to this, but if you can't access Map, the rest of this is inaccessible to you.
I found this article which covers the process in CONNECT edition. Sometimes CE documentation works for V8i in some contexts, but this doesn't, or at least not for me.
So I found this article which covers the process in V8i. From my observation, the next lines of code work.
From my observation, the following lines of code will not work.
In short, I think leaving the brackets off the last entry is fine, but if brackets are left off any preceding entry it will fail to deliver what you would otherwise expect.
Once you've copied the DTY where it belongs and directed your UCF or PCF or CFG to look in that direction, open a fresh session of Microstation. Activate Map as noted above.
Then go to the Tools menu, find Geospatial near the top, then select what for me is the second option to set the alternative GeoCS. You'll find an option to open the library from the button bar (From Library). From there, you'll be able to make copies of projections from elsewhere, paste them into your DTY file, and make edits as necessary. I believe the rest of the process will be simple enough to guess at. (And where it isn't easy enough to guess at, I don't know further at this time.)