Byteformat of a RSA signature

[Christoph Rachinger]

Hi everyone,

this question is probably rather simply to those involved in developing
GPG, maybe some of the user users know the answer as well:
I'm trying to write a program for reading signatures of binary files. For
this, I make use of GPG's SHA1 and RSA implementations (and the MPI
implementation to be able to calculate them). But my problem is the
following: To check whether a file's signature is valid or nor I have to
read the current detached signature into an MPI. But I do not know when
the actual MPI starts, i.e. where I have to start reading with
mpi_data_from_buffer. So I hope anyone can tell me the format of the RSA
signature or just tell me the offset, where I need to start reading the
MPI.
I'm currently using GPG 1.4.11

Thank you
Chris