[postgis-users] srid for NAD83 State Plane Illinois East US Foot

[Ryan D. Enos]

Hi,
I'm new to postgis and gis in general.  I see in the text of the email 
posted here:
http://postgis.refractions.net/pipermail/postgis-users/2005-May/008226.html

that someone once asked about the srid for files from the city of 
Chicago. I am dealing with similar files now and I am having similar 
troubles with the lat/long appearing way off when loaded into Postgres.  
I have determined that I am pretty sure that the SRID I am using is 
incorrect and the previous user was advised to use 102671, which is said 
to be the same as 26971 except that it uses the U.S. foot.  However, 
when I attempt to transform using this SRID in postres, I get the 
following message:
ERROR:  AddToPROJ4SRSCache: Cannot find SRID (102671) in spatial_ref_sys

Is there another SRID that I should be using?

I have searched the spatial_ref_sys table and the closest thing I can 
find using U.S. feet is for NAD27. 

Thanks.
Ryan