it's not hard at all - only you must understand and accept some rules. Briefly :
1. nero wave editor (or similar mus. editing tool f.e. soundforge) , CDmage1-02-B5 , AFS Explorer 2.0 , adxencd - are needed tools
2. i assume that u have (or know how) extracted FILEDATA.ASF from WE7 image
3. BGM01 >main menu<47 sek. 150pl.afs> 150pl_auto.afs> BGM_01.bin
BGM02 >league+cup menu<42 sek. 150pl.afs> 150pl_auto.afs> BGM_02.bin
BGM03 >training menu<_? sek. 110training.afs> BGM_03.bin
BGM04 >ML-menu<48 sek. 150pl.afs> 150pl_auto.afs> BGM_04.bin
BGM05 >ceremony after winning a cup etc.<__87 sek. 170demo.afs> 170demo_ending.afs> BGM_05.bin
BGM21 >Highlights<82 sek. 160game.afs> BGM_21.bin
BGM22 >ceremony(ML)<79 sek. 170demo.afs> 170demo_ending.afs> BGM_22.bin
BGM23 >entering the pitch<64 sek. 170demo_enter.afs> BGM_23.bin
4. If I want to change for example title menu music (BMG_01) = must create NEW BMG_01 file, this means chose your favorite mp3 , open nero wave editor and edit this song to time, that original song have (or short). Now convert sample format (edit menu) to 24 000 Hz stereo or mono and save this song as BMG_01.wav.
5. make directory f.e. music on you root dir C:\ and place you edited BMG_01.wav and adxencd files here
Go to Start --> Run and type in cmd
type cd C:\music
type adxencd BGM_01.wav hit enter
after this some text apear but only bottom number is relevant (sample rate f.e.565178)
type adxencd BGM_01.wav -lps0 -lpe"565178"
now you have new file BMG_01.adx created and can import it in AFS Explorer instead original BMG_01.bin (afs explorer2.0 change adx to bin file automaticly) just make sure, that size of imported file isn't biger that reserved space in right column.
Work with explorer ist over , in CD mage reimport Filedata.afs , scan for corruption and regenerate, rebuild if needed. Burn with favorit burning soft.