There is a table in mysql "psa" database named Components.
mysql> select * from Components;
+-------------------------+-------------------------------+
| name | version |
+-------------------------+-------------------------------+
| apache | 1.3.31 |
| php | 4.3.2-14.ent |
| mod_python | 3.0.3-3.ent |
| bind | 9.2.2-21 |
| courier-imap | 3.0.8-rhel3.build75050130.17 |
| frontpage | 5.0.2.2634 |
| jdk | 1.4.2 |
| tomcat | 4.1.30 |
| logrotate | 3.7 |
| mysql | 3.23.58-1 |
| mailman | 2.1.1-5 |
| postgresql | 7.4.1 |
| phpmyadmin | 2.5.3 |
| phppgadmin | 2.4.2 |
| proftpd | 1.2.9 |
| qmail | 1.03 |
| webalizer | 2.01_10-15.ent |
| rblsmtpd | 0.70 |
| mod_perl | 1.99_09-10.ent |
| perl-Apache-ASP | 2.57-rhel3.build75050130.17 |
| spamassassin | 2.63-0.2 |
| drweb | 4.32.2-rh7_psa |
| drweb-qmail | 4.32-rhel3.build75050130.17 |
| psa-migration-manager | 7.5.2-rhel3.build75050202.14 |
| httpd | 2.0.46-38.ent |
| coldfusion | not_installed |
| psa-qmail | 1.03-rhel3.build75050130.17 |
| psa-proftpd | 1.2.10-rhel3.build75050130.17 |
| psa-logrotate | 3.7-rhel3.build75050130.17 |
| psa-spamassassin | 7.5.2-rhel3.build75050130.17 |
| tomcat4 | 4.1.24-full.2jpp |
| apache2-mod_perl | not_installed |
| psa-bu | 7.5.2-rhel3.build75050130.17 |
| stunnel | 4.04-4 |
| psa-qmail-rblsmtpd | 0.70-rhel3.build75050130.17 |
| psa-tomcat-configurator | 7.5.2-rhel3.build75050130.17 |
| postgresql-server | not_installed |
| psa-api-rpc | 7.5.2-rhel3.build75050130.17 |
| SSHTerm | 0.2.2-rhel3.build75050130.17 |
| psa | 7.5.2-rhel3.build75050130.17 |
| psa-agent | not_installed |
+-------------------------+-------------------------------+
41 rows in set (0.00 sec)
mysql>
So I think plesk just get an information about components version from this table. I am sure it is possible to force plesk to refresh this table, but I don't know how. You can just change the version value by hand in this table. I beleave it will be OK.