Swapfile larger 2 GB ?

Hello * i need to use a swapfile larger 2 GB on amd64. I have read an earlier posting of Andi, that this is possible. Since i still get only 2 GB Swap signatures when calling mkswap my questions: Do i have to enforce a size > 2 GB manually when calling mkswap or do i have to use a patched mkswap ? For those curios, why i don't use multiple swap partitions: i'd like to do suspend to disk on a laptop with 2 GB Mem so i need a littler bit more than those 2 GB continuos swap. TIA Micha