java 1.5 compilation fails in eclipse

feel free to suggest how to work around this but it looks like some of the java code is not 1.5 in the HTTPClient.

Eg. it uses 'enum' which is a reserved word in java 1.5.

the ant build seems to set the java version to 1.4.

Considering the move to java 1.5 is official, it would make sense to me to make all the code 1.5 compliant.

Thanks
Alex

Exception in thread "HTTPS proxy SSL engine" java.lang.Error: Unresolved compilation problems:
The constructor CIHashtableEnumeration(Enumeration) is undefined
Syntax error on tokens, delete these tokens
Syntax error on token "enum", invalid VariableDeclaratorId
Syntax error, insert "AssignmentOperator Expression" to complete Assignment
Syntax error, insert ";" to complete Statement
Syntax error, insert "}" to complete BlockStatements
Syntax error on token "enum", invalid Expression

at HTTPClient.CIHashtable.<init>(CIHashtable.java:152)
at HTTPClient.HTTPConnection.<clinit>(HTTPConnection.java:254)
at net.grinder.tools.tcpproxy.TCPProxySSLSocketFactoryImplementation.createClientSocket(TCPProxySSLSocketFactoryImplementation.java:180)
at net.grinder.tools.tcpproxy.AbstractTCPProxyEngine.launchThreadPair(AbstractTCPProxyEngine.java:347)
at net.grinder.tools.tcpproxy.HTTPProxyTCPProxyEngine$ProxySSLEngine.run(HTTPProxyTCPProxyEngine.java:622)
at java.lang.Thread.run(Unknown Source)