dump to a samba mounted FAT32 disk can't handle bigfiles?

[Joachim Dagerot]

I'm dump-ing to a samba mounted xp machine, it has an external HD
connected through FW and the HD is about 300GB. 

When I try to dump anything larger than 4GB dump gives me a write
error.

I assume this is the big-file limitation in the foreign OS, but I
guess this can be solved by breaking up the dump file in mutiple
volumes.

The man page for dump states this:

[....]
 -B records
The number of kilobytes per output volume, except that if it is not an
integer multiple of the output block size, the command uses the next
smaller such multiple.  This option overrides the calculation of tape
size based on length and density.
[....]

So I thougth this line should create a bunch of 35mb files. But it did
not. Any thouts on this?

>dump -0 -L -a -B 35000 -f /HEMMET2/External_HD/freebsd_usr.dump 
/dev/ad0s1f