Hmm, I can't find the code any-more and I don't want to brick another module before I can unbrick my 2 modules first. But I think I know what my mistake was.:
Instead of :
Dim data As ListOfByte = New ListOfByte
I forgot the New statement and did:
Dim data As ListOfByte = ListOfByte 

After that I did:
data.Add(element)
spi_device.Transfer(data)

I found out about my mistake by running in the debugger, he complaint that I had a null pointer variable or something like that.
My compiler didn't complain and so my module became bricked. So I think it's good practice to debug always first.