Endicia for Mac Walk through:
FileMaker Using Simple Applescript (Version 7)

The way quotes are handled in FileMaker changed between version 6 and 7.

So, instead of the "Perform AppleScript" action in Version 6, you can select the "Open URL" one in Version 7 instead.

That makes the quoting a bit simpler in the Endicia URL Field.

"endicia://newShipment2/?ToAddress=" & First Name & " " & Last Name & "¶" & Company & "¶" & Street 1 & " " & Street 2 & "¶" & City 1 & " " & State Province 1 & " " & Postal Code 1 & ";ReferenceID=" & ReferenceID & ";ToPhone=" & Phone 1 & ";MailClass=" & MailClass & ";WeightOz=" & WeightOz

We have a sample FileMaker database that implements this method available here for download.

Please Note: Due to a bug in the first two releases of FileMakerPro 7, you must update to 7.0v3 for this method to work. (The bug makes all URLs lowercase, and Endicia URLs are case-sensitive).