I am getting nuts with this....

I have an amount in A1: 108.203

And I need to fill A2 that must be 15 characters with the value of A1
and the remain characters before the first number (1) must be fill
with Zeros.

E.I.:
The result must be:
A2= 00000000108.203

Is there a way to do it?
Thanks in advance for your help.