Some resources/information regarding Polycom dial plans (digitmaps) is below.
Example dial plan to replace a leading 0 with 44 on UK calls:
The first part of this dial plan defines what counts as an international call. This will accept any number that starts with two 0s followed by any digit from 1-9 and up to a further 10 digits (this can be increased as necessary by adding more x's). If a call does not match the first part of the dial plan, it will proceed to the second part (separated by |). This part of the dial plan uses the RRR modifiers. Anything between the first two R's is replaced by anything between the second and third R's. Therefore 0 is replaced with 44 in all cases except where the first 0 is followed by a second 0.
Useful guides/links for Polycom dial plans: