I use CR 8.5.0.217 under Windows 2000.  Using CR, I specify a non-custom format ("-1,234  signed integer) on every numeric field of a multi-column report.  Each column has 24 rows and any NULL numbers are initialized to true zero integers.

  

When I load CR and export my report to Excel, the spreadsheet shows all zeroes as true "0" as it should.  HOWEVER, when I link the report call via VB (VB 6.0), the CR displays just fine (all "0"s OK) but the exported Excel file defaults all "0" to "######" fields.  

in crystal create a function that says

if x = 0 then ' ' else totext(x)

replace the field by the function