Is it possible to know how can I increase the length of accessToken field in the UserConnection table.

As I'm working on the Windows Live plugin and getting the following error while trying to authenticate with the API.

Code:
WARNING: Exception while handling OAuth2 callback (PreparedStatementCallback; SQL [insert into UserConnection (userId, providerId, providerUserId, rank, displayName, profileUrl, imageUrl, accessToken, secret, refreshToken, expireTime) values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)]; Value too long for column "ACCESSTOKEN VARCHAR(255) NOT NULL": "'EwAgAq1DBAAUlb... (728)"; SQL statement:

insert into UserConnection (userId, providerId, providerUserId, rank, displayName, profileUrl, imageUrl, accessToken, secret, refreshToken, expireTime) values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?) [22001-159]; nested exception is org.h2.jdbc.JdbcSQLException: Value too long for column "ACCESSTOKEN VARCHAR(255) NOT NULL": "'EwAgAq1DB... (728)"; 

SQL statement:
insert into UserConnection (userId, providerId, providerUserId, rank, displayName, profileUrl, imageUrl, accessToken, secret, refreshToken, expireTime) values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?) [22001-159]). Redirecting to /signin
Thanks,
Sachin