I realize this post is very old now, but I am trying to append a shapefile to an existing feature layer also. Can you give me some more information on how you did that?
an another option is to create a geoprocessing service on your Server to do it.
The script will have as input parameter zip file with the Shapefile contents.
the input zip will extracted and then you can load the data on a feature class.
here is a code example for
#extract the zip
zf = zipfile.ZipFile(inShpZip)FeaturesPath = arcpy.env.scratchFolder + "/zipSHPExtract" zf.extractall(FeaturesPath)
#find the shp shpFilesFromZip = glob.glob(FeaturesPath + "/*.shp")
outFeatures = arcpy.env.scratchGDB + "/outFeatures1" arcpy.CopyFeatures_management(shpFilesFromZip, outFeatures)
Retrieving data ...