I don't know if this will help you in Model Manager, but when I have an issue with a table that has more than 32 characters, I use the following macro in Studio:
/* Define the macro variables */
%let incaslib = ; /* CAS library where the table is located */
%let casdata = ; /* Name of the CAS table you want to rename */
%let casout = ; /* Name of the table you want to set in CAS */
/* Macro to load and promote a table in the CAS environment */
%macro sas_load_promote_cas(casout=, incaslib=, casdata=);
/* Drops the table in the CASLIB and loads the table into CAS */
proc casutil;
droptable incaslib="&incaslib." casdata="&casdata." quiet;
load casdata="&casdata." incaslib="&incaslib."
outcaslib="&incaslib." casout="&casout.";
run;
/* Promotes the table to the CASLIB */
proc casutil;
promote incaslib="&incaslib." casdata="&casout."
outcaslib="&incaslib." casout="&casout.";
quit;
%mend sas_load_promote_cas;
/* Call the macro with the defined variables */
%sas_load_promote_cas(casout=&casout, incaslib=&incaslib, casdata=&casdata);
This way, I rename the table to a shorter name so it can be used within the SAS environment.