Hi,
The Upsize tool does not transfer data in sql mode
It builds the table structure but does NOT transfer the data (I tested it 
also with the MdiDemo)

Docs:
mode='sql': If sql is specified as the upsize mode, the table structure is 
created on the SQL server. Also, the data is transferred to the server. 
However, the resulting SQL table does not support the ISAM-navigational 
access pattern. Only Universal SQL as a relational data access pattern can 
be used to access the data from within the application.

The only change below from the original code is in the last row I changed 
the "isam" to "sql"

<?xml version="1.0" encoding="iso-8859-1" standalone="yes"?>
<config>
<database_engines>
  <dbebuild name="FOXCDX">
     <storage name="FOXDBE"/>
     <order   name="CDXDBE"/>
  </dbebuild>
  <dbeload name="pgdbe"/>
</database_engines>
<connection name="test"
            dbe="pgdbe"
            srv="localhost"
            uid="postgres"
            pwd="postgres"
            database="xppsamples1"/>
<table name = "customers"
       dbe  = "foxcdx"
       dbf  = "..\..\data\northwind\dbf\customers.dbf">
</table>
<upsize table="customers" connection="test" mode="sql"/>
</config>

Thank you
Itai Dishon