Steven T,
Great news, I have a solution that I have tested that will hopefully get this squared away.
What I did was mimic your setup, to a degree, with a custom date field. While in my publish page, I used Safari’s built-in web inspector to inspect the element of the “Fixed/Localized” dropdown. What this allowed me to see what the “raw” field name for that dropdown. In my case it was “field_offset_3” (for reference, my date field’s raw name is field_id_3). Safecracker will respect and use these “raw” values, but obviously it’s is easier to use the field names you give them. For this to work, I made an input type=“hidden” in my safecracker template with the value=“n” (the value of the “fixed” option in the dropdown). I used this template to submit an entry, and when I looked at the entry in the Control Panel, the custom date field was set to “Fixed” 😊
Here is my template for your reference:
{exp:safecracker channel="journal" return="main/awesome"}
<label for="title">Title</label>
<input type="text" name="title" id="title" value="{title}" size="50" maxlength="100">
<label for="url_title">URL Title</label>
<input type="text" name="url_title" id="url_title" value="{url_title}" maxlength="75" size="50" />
Date
<input type="text" name="entry_date" value="{entry_date}" maxlength="23" size="25" /></p>
<input type="text" name="my_date" value="{my_date}">
<input type="hidden" name="field_offset_3" value="n" />
<textarea name="body"></textarea>
<input type="submit" name="submit" value="Submit" />
{/exp:safecracker}
I’ll just point out again that *your* raw field names will most likely be different, so use whatever means you are comfortable with to determine that. Also note that any *other* custom date fields you create in the future will have different raw values. The raw value will be consistent *within* the same channel fields group, however.
I hope this helps, and let us know if we can be of further assistance.
Cheers,