.NET webservice pdb deployed still no line numbers

Question

If anyone can help this one I would appreciate it, I have searched and built for a while.

1. website project
2. build using CCNET
3. Built using msbuild and config DebugType=pdbonly
4. Merge all files into single assembly using aspnet_merge and -a -debug
5. pdb is in same directory as .dll
6. debug=true in web.config
7. No impersonation going on
8. Framework 4.0 (still checked, no reference to deployment)
9. Captured via ex.ToString()

Sample stack trace

System.InvalidCastException: Conversion from type 'DBNull' to type 'Integer' is not valid. at Microsoft.VisualBasic.CompilerServices.Conversions.ToInteger(Object Value) at UserControls_OpportunityManagement.GetReferralMethodIDByDialedNbr(String DialedNumber)