[CrazY.]

Here is an example, needs some conditions to avoid problems, but is the base:

public fw_UpdateClientData_Post(id, sendweapons, cd_handle)
{
    // Block default sounds and animation of a weapon
    set_cd(cd_handle, CD_flNextAttack, get_gametime() + 0.001)
}

public fw_PlaybackEvent(flags, invoker, eventid, Float:delay, Float:origin[3], Float:angles[3], Float:fparam1, Float:fparam2, iParam1, iParam2, bParam1, bParam2)
{
    if (((1<<eventid) != g_iEventId))
        return FMRES_IGNORED;

    if (!(1 <= invoker <= g_MaxPlayers))
        return FMRES_IGNORED;

    // PlaybackEvent (play custom sounds to all clients, don't only the owner)
    playback_event(flags | FEV_HOSTONLY, invoker, eventid, delay, origin, angles, fparam1, fparam2, iParam1, iParam2, bParam1, bParam2);
    return FMRES_SUPERCEDE;
}

public fw_PrecacheEvent_Post(type, const name[])
{
    if (!equal("events/weapon_event.sc", name))
        return;

    // Precache gun event
    g_iEventId |= (1<<get_orig_retval())
}

public fw_Item_Deploy_Post(entity)
{
    new id = get_pdata_cbase(entity, 41, 4)

    // Play 'draw' animation
    Util_PlayWeaponAnim(id, 1)

    // Play 'draw' sound
    emit_sound(id, "weapons/draw.wav", VOL_NORM, ATTN_NORM, 0, PITCH_NORM)
}

public fw_Weapon_PrimaryAttack_Post(entity)
{
    new id = get_pdata_cbase(entity, 41, 4)

    // Play 'fire' animation
    Util_PlayWeaponAnim(id, 3)

    // Play 'fire' sound
    emit_sound(id, "weapons/fire.wav", VOL_NORM, ATTN_NORM, 0, PITCH_NORM)
}

stock Util_PlayWeaponAnim(id, sequence)
{
    entity_set_int(id, EV_INT_weaponanim, sequence)

    message_begin(MSG_ONE_UNRELIABLE, SVC_WEAPONANIM, .player = id)
    write_byte(sequence)
    write_byte(entity_get_int(id, EV_INT_body))
    message_end()
}