SQLDescribeParam not defined: any workaround?

From what I've read about the win32 (and perhaps all platforms)
Postgres ODBC driver, SQLDescribeParam is not implemented. I discovered
this while running some software that tries to use it. It got back the:

Driver does not support this function (SQLSTATE: IM001)

message, of course.

The reason my software was calling this function was to determine the
scale and data type of the parameters to a function before issuing a
prepared statement to that function.

Is anyone aware of a workaround via the existing (official) ODBC drivers
whereby I could interrogate the function I'm about to call to get more
detailed information about each parameter?

If not, what strategies do others employ to handle this? Right now, my
best shot is to just define my local buffers to 255 bytes or so and go
from there, but clearly that's not flexible or elegant.

Thanks,

jl