[Scribus] Registration marks

[Tobias Hilbricht]

Dear readers of this list,

how do you produce registration marks for four-colour printing with Scribus?  
That is crosses consisting of 100 % C, M, Y, K each helping to place the four 
separations exactly? I noticed that when I create separations with Scribus 
100 % C,M,Y,K is converted into just 100% K, which is not the same when it 
comes to registration marks. The same with 100% C,M,Y, which comes out as 
100% K. I am using Scribus 1.2.1 with gs 8.51. 

Thanks for helpful hints in advance

Yours sincerely

Tobias Hilbricht