scatterlist and cryptoapi question

[Joy Latten]

I have been reading PKCS#1v2.1 and trying to figure
out the best way to implement the RSAES-OAEP schemes within the 
kernel cryptoapi. For RSAES-OAEP-ENCRYPT, one of the 
inputs is a Label, which will be hashed, lhash = Hash(L);
Therefore shouldn't this info be input as a scatterlist
to my rsaes-oeap-encrypt() routine rather than my routine putting it
into a scatterlist and then hashing it? Because Label is not very defined
in the doc, I am thinking it is possible it could be across pages...
The doc currently defines/defaults Label to empty string, but
states the length of L is the input limitation of the hash function. 
Thanks for any help as I am still learning scatterlist.

Joy