newbie problem

[Olivier Scalbert <olivier.scalbert@algosyn.com>]

Hello,

I am doing a little package and I have problems just for writing the 
specification ...

In short, this package should offer services to create sequential files 
that store stereo sound samples.

Here is the code:

with Sequential_Io; -- Problem 2  not nice should be hidden but how ?

package adasound is

     type Amplitude_T is new Float;
     type Frequency_T is new Float;
     type Time_T      is new Float;

     type Stereo_Amplitude_T is record
         Left : Amplitude_T;
         Right: Amplitude_T;
     end record;

     type Als_File_T is private;

     function  Als_Create(File_Name: String) return Als_File_T;
     procedure Als_Write(Als_File: Als_File_T; Stereo_Amplitude: 
Stereo_Amplitude_T);
     procedure Als_Close(Als_File: Als_File_T);

private
     package Stereo_Amplitude_Io is new Sequential_Io (Stereo_Amplitude_T);

     type Als_File_T is record
         File_Type: Stereo_Amplitude_Io.File_Type; -- Problem 1 !!
         -- perhaps more stuff later
     end record;

end adasound;

Problem 1: it does not compile !
adasound.ads:23:10: completion of nonlimited type cannot be limited
adasound.ads:23:10: component "File_Type" of type "Als_File_T" has 
limited type

Problem 2: how to avoid the first "with Sequential_Io;" ?

Thanks to help me !

Olivier.