1. Create a data source in the "Data Layer" tab. Name it 's_fid' and make the type 'first party cookie'
2. Go into your SiteCatalyst mapping. Select the 's_fid' cookie as the source, and then map it to the props/eVars you'd like to send it to.
Any time the 's_fid' cookie is present, it should now be sent to that destination for SiteCatalyst. This means that on the very first pageview, the cookie may not be present since it hasn't been created by the SiteCatalyst library yet, but it should be available on subsequent pageviews.
I think you can use the dynamic variable setting for this. (D=s_fid)
You can do this one of two ways:
1) Create a Set Data Values Extension like:
Set: s_fid_cookie To: Text -> D=s_fid
Then you will map s_fid_cookie to the prop/eVar you want to send the value to. Let's say you mapped it to eVar1. This will show up in the Server Call to SiteCatalyst like:
eVar1 = D=s_fid
This tells SiteCatalysts servers to pull the value from the s_fid cookie and set it in eVar1.
2) In your doPlugins function you can use this:
s.eVar1 = D=s_fid;
That's it. This will do the same thing but is setting the variable a different way.