Battery pack Siemens A35

I've a Siemens A35 with battery problems.

I disassembled the battery pack (NiMh, 600MaH, 3,6V). It's composed by 3 AAA cells.

The cells are blue, the serial number is 17S0206LNT

The connection is:

• B A T T E R Y P A C K -

After the charging process, the whole battery pack is at 4,24 V, each cell at 1,42V.

I wonder if I can change the cells with new NiMh ones. Could it work? What kind of AAA NiMh cell should I use? MaH?

Thanks a lot

Luca