handle huge file size in file receiver

I have file(NfS) to file(Ftp) scenario  the receiver file failing because of my huge data(nearly 20KB)  i am using Message mapping functionality i cant use file check machanisam to split my file .could you share some ideas how can i achieve this requirement  .

file ---> PI (7.4 java)--->File(Ftp)  20 to 25 KB)

how can i handle huge data in FIle receiver side ?