Use the "Attach to Process..." feature in .NET.
1. Install your plug-in.
2. Start Photoshop normally.
3. In .NET use "Process..." menu item (i think it is in Debug menu) and attach to the running Photoshop.
4. Set your breakpoints and execute your plug-in.
NOTE: Depending on your plug-in, you can detach, fix bugs, build, attach, debug. Very efficient way of fixing bugs without relaunching Photoshop.
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