How to Retrieve the Default Photoshop Color Spaces?

Specifically, I would like to be able to access the actual color profiles the user has chosen as the default RGB and Grayscale color spaces, so I can do the same things as Photoshop with untagged images.  I'm defining functionality to be similar to that of Photoshop itself when Photoshop does not provide a pointer to a document color profile via gFilterRecord->iCCprofileData.

I'm thinking along these lines:

1.  Detect if Photoshop is the host, and if not, stop and use internal defaults (e.g., sRGB).

2.  Use the property suite to ask Photoshop what the user's prefs for the appropriate color category is, depending on the image mode received.

What I don't know are the specifics, nor whether Photoshop is likely to provide a pointer to the profile in memory or whether I'll have to go open it myself (either way would be no problem).

Do you know any of the specific callbacks I'll need to code?

Meanwhile I'll be scouring the documentation.

Thanks.

-Noel